This morning I see that the bits for Exchange 2003 SP1 have hit the web (download here). This is excellent news, as SP1 has lots of great new features you want (this list taken from the announcement page, linked above):
Plus, there's a handful of cool, new “Web Release“ tools available (Note: this is not an exhaustive list):
And, of course, one that lots of folks have been waiting for -- the new Intelligent Message Filter (IMF). You can also get the new MOM management pack for IMF. See more about IMF here, and in particular, read the IMF Deployment Guide.
Also, several “technical library guides” have been added or updated for SP1:
Whew... That's a lot of links. Enjoy!