You can get and build the real latest version mutt from http://www.mutt.org. Make sure you read the INSTALL file if you need IMAP or POP support. This package really should be removed and replaced with the official link, since the one here no longer works. The ratings below are for the mutt mail client. The 'Mutt for OSX 1.2.5i' port isn't even worth rating.
This one seems to require Fink (there is a "sw" directory).
I'm still looking for a standalone GUI mutt. Something that would use the Mutt "engine" (?) if the comparison between gecko for the web and Mutt for the mail is relevant.