I've put together a list of articles which cover common questions on Exchange Web Services (EWS).  These links cover issues from starting out to common problems.  I hope they help.  Please let me know if there is anything important to add.

 

Getting Started:

 

 

Web Services

http://msdn.microsoft.com/en-us/library/aa579187(EXCHG.80).aspx

 

Exchange Web Services Architecture

http://msdn.microsoft.com/en-us/library/aa579369(EXCHG.80).aspx

 

Exchange Web Services Developer Overview

http://msdn.microsoft.com/en-us/library/cc535017(EXCHG.80).aspx

 

Exchange Web Services Client Development

http://msdn.microsoft.com/en-us/library/bb204040(EXCHG.80).aspx

 

Inside Microsoft Exchange 2007 Web Services

http://www.microsoft.com/MSPress/books/10724.aspx

 

Samples:

 

What's New in Exchange Server 2007 SP1 Extensibility

http://msdn.microsoft.com/en-us/library/bb608442(EXCHG.80).aspx

 

Versioning Requests (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb856547(EXCHG.80).aspx

 

Exchange Autodiscover Tasks

http://msdn.microsoft.com/en-us/library/bb204078(EXCHG.80).aspx

 

Finding Folders (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa493892(EXCHG.80).aspx

 

Finding Items (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563373(EXCHG.80).aspx

 

Deleting Items (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb204091(EXCHG.80).aspx

 

Finding the Message Body

http://msdn.microsoft.com/en-us/library/bb508824(EXCHG.80).aspx

 

Creating E-mail Messages (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563009(EXCHG.80).aspx

 

Sending E-mail Messages (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563049(EXCHG.80).aspx

 

 

Creating Contacts (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563318(EXCHG.80).aspx

 

Updating Contacts (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa493909(EXCHG.80).aspx

 

Working with Time Zones in the Exchange Web Services GetUserAvailability Operation

http://msdn.microsoft.com/en-us/library/bb655859(EXCHG.80).aspx

 

Handling Meetings (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa494190(EXCHG.80).aspx

 

Best Practices for Using Exchange Web Services for Calendaring Tasks

http://msdn.microsoft.com/en-us/library/bb738399(EXCHG.80).aspx

 

Creating Appointments (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563060(EXCHG.80).aspx

 

Sample: Using Calendar Views with EWS.

http://blogs.msdn.com/webdav_101/archive/2009/01/05/sample-using-calendar-views-with-ews.aspx

 

Exchange Task Item Tasks

http://msdn.microsoft.com/en-us/library/bb204096(EXCHG.80).aspx

 

Getting User Availability (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa494212(EXCHG.80).aspx

 

Using Pull Subscriptions (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa579617(EXCHG.80).aspx

 

Push Notification Sample Application (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb204063(EXCHG.80).aspx

 

Using Name Resolution (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa493895(EXCHG.80).aspx

 

Synchronizing Mailboxes (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/aa563026(EXCHG.80).aspx

 

Converting Identifiers (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb856559(EXCHG.80).aspx

 

Managed Folder Selector

http://msdn.microsoft.com/en-us/library/bb408416(EXCHG.80).aspx

 

Problems:

 

Customizing Get and Find Responses in Exchange Web Services

http://msdn.microsoft.com/en-us/library/cc720859(EXCHG.80).aspx

 

EWS DaysOfWeek cannot be set to enumerated days.

http://blogs.msdn.com/webdav_101/archive/2007/11/29/ews-daysofweek-cannot-be-set-to-enumerated-days.aspx

 

OUTBOX: Understanding and Fixing Slow Exchange Web Services Code (Part 1)

http://blogs.msdn.com/mstehle/archive/2008/07/17/outbox-understanding-and-fixing-slow-exchange-web-services-code-part-1.aspx

 

KB: Exchange Web Services Does Not Honor Inherited Permissions from Server Level Objects

http://blogs.msdn.com/mstehle/archive/2007/09/07/kb-exchange-web-services-does-not-honor-inherited-permissions-from-server-level-objects.aspx

 

OUTBOX: Configuring and Using Exchange Web Services Impersonation in Exchange 2007

http://blogs.msdn.com/mstehle/archive/2007/07/30/outbox-configuring-and-using-exchange-web-services-impersonation-in-exchange-2007.aspx

 

How to access or change OWA settings for Exchange 2007/2003/2000?

http://blogs.msdn.com/webdav_101/archive/2008/01/31/how-to-i-change-owa-settings-using-webdav-or-ews-for-exchange-2007.aspx

 

HOWTO: EWS: Update IsRead Flag for items using Exchange Web Services

http://blogs.msdn.com/vikas/archive/2007/11/30/howto-ews-update-isread-flag-for-items-using-exchange-web-services.aspx

 

Installation:

 

Exchange Web Services Client Development

http://msdn.microsoft.com/en-us/library/bb204040(EXCHG.80).aspx

 

How to obtain the latest service pack or update rollup for Exchange 2007

http://support.microsoft.com/kb/937052

 

Configuring Exchange Impersonation (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb204095(EXCHG.80).aspx

 

Configuring Exchange Web Services for Proxy Requests (Exchange Web Services)

http://msdn.microsoft.com/en-us/library/bb856576(EXCHG.80).aspx

 

Training:

 

Introduction to Exchange Web Services in Exchange 2007

http://msdn.microsoft.com/en-us/library/bb408417.aspx

 

Introduction to Exchange Web Services in Exchange 2007, Part 2

http://msdn.microsoft.com/en-us/library/bb421489(EXCHG.80).aspx

 

Introduction to Exchange Web Services in Exchange 2007, Part 3

http://msdn.microsoft.com/en-us/library/bb508825(EXCHG.80).aspx

 

Migrating to Exchange Web Services, Part 1: Messaging

http://msdn.microsoft.com/en-us/library/cc720858(EXCHG.80).aspx

 

Migrating to Exchange Web Services, Part 2: Calendaring

http://msdn.microsoft.com/en-us/library/cc788131(EXCHG.80).aspx

 

Migrating to Exchange Web Services, Part 3: Search

http://msdn.microsoft.com/en-us/library/cc795474(EXCHG.80).aspx

 

Migrating to Exchange Web Services, Part 4: Contact Management

http://msdn.microsoft.com/en-us/library/cc974151(EXCHG.80).aspx

 

Exchange Web Services Reference

http://msdn.microsoft.com/en-us/library/bb204119(EXCHG.80).aspx

 

FYI: Exchange 2007 SP-1 Extensibility (Development) Updates

http://blogs.msdn.com/mstehle/archive/2007/11/29/fyi-exchange-2007-sp-1-extensibility-development-updates.aspx

 

 

Other:

 

Selecting Development Technologies for Exchange

http://msdn.microsoft.com/en-us/library/aa579216(EXCHG.80).aspx

 

Exchange Development Technologies

http://msdn.microsoft.com/en-us/library/aa579216(EXCHG.80).aspx

 

Scripting Exchange Web Services (2007) with VBS and Powershell

http://gsexdev.blogspot.com/2006/12/scripting-exchange-web-services-2007.html

 

Exchange Server 2007 Legacy API Property Mapping

http://www.microsoft.com/downloads/details.aspx?FamilyID=CDE26EA9-5647-448F-A5E6-AE094A882EE5&displaylang=en

 

HOWTO: EWS: Find all folders inside a parent folder, helpful in generating a folder tree

http://blogs.msdn.com/vikas/archive/2007/11/14/howto-ews-find-all-folders-inside-a-parent-folder-helpful-in-generating-a-folder-tree.aspx

 

EWS - Csharp - List unread inbox messages using a restriction

http://blogs.msdn.com/webdav_101/archive/2007/11/29/ews-csharp-list-unread-inbox-messages-using-a-restriction.aspx

 

HOWTO: EWS : Get SMTP address from X500 address

http://blogs.msdn.com/vikas/archive/2007/09/05/howto-ews-get-smtp-address-from-x500-address.aspx

 

Exchange Web Services and Internet Message Headers

http://blogs.msdn.com/stephen_griffin/archive/2007/02/09/exchange-web-services-and-internet-message-headers.aspx

 

Exchange Web Services and MAPI Props

http://blogs.msdn.com/stephen_griffin/archive/2006/12/19/exchange-web-services-and-mapi-props.aspx

 

White Paper: Exchange 2007 Autodiscover Service

http://technet.microsoft.com/en-us/library/bb332063.aspx

 

White Paper: Exchange 2007 Client Access and SSL

http://technet.microsoft.com/en-us/library/cc164344(EXCHG.80).aspx

 

 

Additional Tips:

 

·   Always set the ChangeKey whenever possible – it speeds up processing.

 

·  If at all possible, have SP1 installed for Exchange 2007.  There are a lot of fixes and enhancements which you will likely need.  Be sure to set the Exchange2007_SP1 header when going against Exchange 2007.