Afaik 
Ximian's Exchange connector is the only software that allows you to connect to exchange servers using Microsoft's protocols, any mail client such as standard Evolution, KMail, Pine, etc etc should be able to connect using IMAP or POP though.
The exchange connector isn't free though, don't remember how much it costs, but it should be on their site.
Oh and it only works with Exchange 2000, not 5.5 or earlier.