Here’s a link to a page on the official website of the Chinese Olympic Committee with a nice summary of Yang Style taijiquan. I know there was some discussion here a while ago about taijiquan in the Olympics.
This page doesn’t really shed any light on what role taijiquan will have in the 2008 Olympics, but it’s nice to see the reference. You can explor links to other categories, including this list:
If you don’t have Chinese fonts installed on your computer, just click “cancel” if a window appears about installing the fonts. The pages are in English, and you should have no trouble viewing them. I haven’t yet read through all of these pages carefully, but they seem to contain some good information, geared toward the general public rather than experts.