Yeah, I'm having the same problem with Entourage. It won't send at first - takes like 5 minutes and gives me an error. It usually sends the 2nd time - but I have to wait for that error message to pop up first. Any ideas about this?? It's pretty annoying. I don't have any problems with my school e-mail account (Entourage is the IMAP client for both).
Adam, you can go into Outlook preferences and tell it to check e-mail automatically every 5 or 10 minutes or whatever.
Dreamhost staff, can you help with the IMAP client issue? It's wicked annoying for me - and sounds like Adam can't send anything at all.