SquirrelMail. Webmail for nuts. Sounds weird, but it rocks. It's in PHP (I'd personally prefer perl) but it still works.
I never could get imp to work properly, but I tried squirrel and eventually just forgot about imp & horde. The communication with the server is over the IMAP protocol, so it doesn't actually matter which mail store format you use (or which IMAP server, for that matter, you could probably use exchange if it's got around to implementing IMAP properly yet). Try it out. I like it, my customers like it, and it rocks. Matthew King -- GIT/CM d+(-) s++:- a-->? C++++ UL++++$ P+++>++++ L++>++++ E>++ W--$ N o? K++ w--- O-- M V? PS+>+++ PE-- Y+>++ PGP++@ t+ 5- X- R tv b+++>++++ DI++ D++ G e(*) h!>- r--- y->+++