I’ve been working with RoundCube, which is an Ajaxy webmail interface to an IMAP server. The software is still in beta, but I’ve been impressed with it so far. I’ve integrated into hooah.com‘s site, so that it matches the rest of their site and had to hack it up a bit to add some dynamic content. I’ve also just installed it for testing on another mail server that I use to see if I can find any bugs in it.
There are a couple features I’d like to see implemented.  It would be nice to be able to change your email account password from the preferences section.  Also, I’d like to set up a more transparent way to have it look up the backend server based on your email domain. Guess I’ll subscribe to their dev list and see if I can contribute any code.
Brandon-
Looks like a nice interface. I will have to take a more detailed look at it when I am able to.
– Mark