EvokeTV is a site doing a lot of what I wished TiVo would do. You create an account, then track shows you want to record. You can rate a TV series as well as individual episodes and they even offer RSS feeds of your show schedule. It's a snappy, ajax interface that is easy to search for shows and get info on them. They even offer a show-sharing feature for bloggers (complete with RSS feed). Here's a list of two shows I tape each week.
Ideally, it'd be great if these features were incorporated into TiVo's online scheduling service (or even cable/satellite DVRs) so that clicking a show would automatically set a recording or season pass in my TiVo. The show sharing is also a feature I'd love to see at TiVo. Netflix offers a similar feature and it's great for finding new movies that your friends enjoyed. The sharing of shows is simple and straightforward, nothing like the hacking I had to go through to reproduce my now playing list last year.
Here's a screenshot of the interface in action. Be sure to also check out their blog which offers tips and new features as they are announced.