Google Gmail Apps Thunderbird and iPhone Resources

Turn Thunderbird into the ultimate Gmail IMAP client
How to get Thunderbird operating with Gmail:
http://lifehacker.com/software/geek-to-live/turn-thunderbird-into-the-ultimate-gmail-imap-client-314574.php

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:
http://mail.google.com/support/bin/answer.py?hl=en&answer=77657

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:
www.youtube.com/watch?v=uQ22euWXYog

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:
www.google.com/a/help/intl/en/admins/pdf/google_apps_imap_migration.pdf