Get started with GMail
Google's Gmail application has some powerful features that probably weren't available in your old mail program, while a few things might work differently.

Google Mail ‎‎(GMail)‎‎ Overview

Can't find something? FAQs & troubleshooting
Other resources

Gmail Search & Keyboard shortcuts
Keep this cheat sheet handy.
Explore Google Labs

Enable offline mail, Gmail superstars, Undo send, and much more.