The other day I put up a full-feature tutorial on how to use mutt on OS X (most of it is applicable to any other OS, of course... there are very few bits that are OS X specific). Thanks to a hint on macosxhints.com, this article is becoming one of the most popular on the site, with over 1900 views in 5 days. Not too shabby.

I'll probably update it a bit in the next few days to include info on using imap with mutt (without using fetchmail, which is what I normally do).