This is not a new site, but it's one I've been meaning to mention for a while.
UGTV is Charlie Arehart's online repository of recorded user group presentations, and there are now 88 presentations posted (including two of mine). While most of the presentations are ColdFusion related, there are also presentations on SQL, Flex, Apollo, Ajax, Acrobat, and more. An RSS feed is also available so you can easily keep track of new recordings as they are posted.
Finally, if anyone knows of any recordings not yet listed, they may be added by anyone in just seconds. I plan to add still more functionality over time.