Thanks for referring to this site, MPoWerMAN. I'm happy to have a dedicated site for X3's as well.
I would also like to point attention to the most excellent BMW On-Line Parts Catalog, which is referenced off the x3world home page. It is the BEST thing since sliced bread, and I am so happy to finally have part numbers for the interior trim pieces as well as the euro clear corner lenses. It's set up really well, with exploded diagrams and a nice parametric-type search design. You can't buy directly from that site yet, but hopefully will be able to soon. Finally, being able to refer to the exact pieces I want (and having price estimates), I'm on cloud 9!