We just refreshed the downloads of the SharePoint SDKs on the Microsoft Download Center to reflect the many recent updates and enhancements to the documentation since RTM.  You should first uninstall any previous versions of the SDK installed on your machines through Control Panel.

Get the updated SDKs today!

• Office SharePoint Server 2007 SDK (Version 1.1)
  Installs to %SystemDrive%\2007 Office System Developer Resources\SharePoint Server 2007 SDK\
  
• Windows SharePoint Services 3.0 SDK (Version 1.1)
  Installs to %SystemDrive%\Windows SharePoint Services Developer Resources\Windows SharePoint Services 3.0 SDK\

Here are the details of what has changed...

What's New in the Windows SharePoint Services SDK

New conceptual sections:

• Content Migration
• Change Log and Synchronizing Applications
• Creating Declarative, No-Code Workflow Editors

Procedural topics:

• How to: Create a Custom Field Type and Field Control
• How To: Extend the STSADM Utility

Schema reference topics for the following schemas:

• Content Migration XML Schema Reference: Contains over 180 element topics that detail the eight migration schemas
• Workflow Configuration Schema

Greatly expanded Class Library Reference material for over 300 types in the following namespaces:

·         Microsoft.SharePoint

·         Microsoft.SharePoint.Administration

·         Microsoft.SharePoint.Deployment

·         Microsoft.SharePoint.EmailIntegration

·         Microsoft.SharePoint.Navigation

·         Microsoft.SharePoint.MobileControls

·         Microsoft.SharePoint.StsAdmin

·         Microsoft.SharePoint.WebPartPages

·         Microsoft.SharePoint.WebControls

·         Microsoft.SharePoint.Workflow

As well as expanded reference material for the following Web Services:

·         Authentication Web Service

·         Copy Web Service

This update also includes numerous updates and revisions to existing SDK content.