For those of you lucky enough to have a Google GMail account, someone wrote Pop Goes The GMail, which forwards GMail messages via the conventional POP3 protocol to your usual e-mail application. This might defeat the purpose of using GMail in the first place for some, as the web interface has its advantages, but I personally like the flexibility this offers.

By the way, I still have several GMail invitations left, so if anyone would like one, let me know and I'll consider your request. ;-)