Google Gmail Apps Thunderbird and iPhone Resources
How to get Thunderbird operating with Gmail:
How do actions sync in IMAP?
Gmail uses a system of labels, which can be mapped to folders in conventional email clients. This page explains how conventional folder-based clients interpret labels, stars and actions such as message moving:
How to set up IMAP-based Gmail in the iPhone
This video shows you how to set up an iPhone for IMAP-based Gmail access:
Google Apps IMAP migration: Best approaches for large migrations
This step-by-step guide takes you through the process for migrating larger groups of email accounts from an on-site IMAP server to Gmail: