Gmail is currently down. But they say I can access it through imap. How do I do this?
See this Google article: IMAP or POP to access your gmail.
Note: these steps must have been done before you try to access your gmail account using a POP or IMAP email client.
You can use Gmail offline if you install Google Gears. Outlined here http://gmailblog.blogspot.com/2009/01/new-in-labs-offline-gmail.html