Service Descriptions

http://www.microsoft.com/download/en/details.aspx?id=13602

Deployment Guide and Deployment Readiness Tool

http://community.office365.com/en-us/f/183/p/1541/5095.aspx

Service Updates Wiki

http://community.office365.com/en-us/w/office_365_service_updates/default.aspx

Office 365 Technical Blogs

http://community.office365.com/en-us/b/office_365_technical_blog/default.aspx

Office 365 SSO Content Map

http://community.office365.com/en-us/w/sso/default.aspx

Exchange Online Performance Guide

http://community.office365.com/en-us/f/183/t/45466.aspx

Quickstart Online for Partners

https://quickstartonlineservices.com

Forum Assistant

http://www.microsoft.com/download/en/details.aspx?id=27547

Exchange PST Catpure

http://www.microsoft.com/download/en/details.aspx?displaylang=en&id=28767

Office 365 Desktop Readiness

http://www.microsoft.com/online/office365-desktop-readiness-tool-form.aspx

Exchange Remote Connectivity Analyzer

https://www.testexchangeconnectivity.com/

Who Can Federate with Lync Online Tool

http://gallery.technet.microsoft.com/Who-Can-Federate-Tool-a9e00d23

Exchange Federation Discovery Tool

http://gallery.technet.microsoft.com/Exchange-Federation-fdf8a324

MessageOps Office 365 Tools

http://www.messageops.com/software

Twitter:  @Office365

Youtube

http://www.youtube.com/microsoftoffice365