Outlook and Outlook Web Access Users from Exchange 2010
Here are some tips for making the switch from Microsoft Exchange 2010 to Google Apps. 
Switching from Microsoft Exchange 2010
Life After Microsoft Outlook®

Quickly learn to accomplish some of the same tasks in Gmail that you're used to doing in Outlook.

Print this guide out and keep it handy as you begin using Gmail.
 What is not migrated to Gmail Public Folders, Messages larger than 25MB, Rules, Signatures, Shared Mailboxes, Category definitions, Category assignments, etc. 
What's not available in Gmail  See features you might be used to in Outlook mail  that aren't in Gmail.
Switching form Microsoft Outlook®: Gmail and Calendar

Self-paced training (short clips - 1 hour total) A comprehensive introduction to switching from Microsoft Outlook® to Google Apps. Covers threaded email conversations, contacts, labels, mail filters, calendar events, syncing events from Outlook, and more.

Synchronizing with Outlook 
Want to keep using Outlook for awhile? Try Google Apps Sync for Microsoft Outlook®.
  1. Install Google Apps Sync on your own computer.

  2. Learn to use Google Apps Sync.
Google Apps Sync for Microsoft Outlook® is a plug-in for Outlook 2010 that syncs mail, calendar events, contacts, and notes between Outlook and your Google Apps account.