This is a repost (old nickname nolonger in use) (original posting date was 21 Dec 2004)
So now you got it's code compiled (the code of Evolution) nothing is stopping you from exploring it and perhaps making contributions? I suggest you take a look at the plugins/ directory. There's lots of work todo! The Evolution dudes organise an IRC-meeting from time to times. Hackfests. Join the next one?
Also check out the developer pages for Evolution.
Oh and Damien: I'm very interested in that GnomeMeeting and GAIM integration -topic. What can be done to still get some integration between Gaim and GnomeMeeting going? Or perhaps with other Instant Messaging clients?
My personal opinion on Desktop Integration is that a (new) foundation like freedesktop.org should focus on this subject and get projects to work together.