Logabottle.com uses AJAX goodness alongside Google Maps to allow you to keep an online repository for all the wines you drink. It allows you to show the location on the map, your own comments and ratings for the bottle, it has a wine guide so you can learn more, and coming soon are wine clubs, so that all the users can review a wine at the same time.
The site allows other users to comment on your page as well, so a sense of community is already evolving on the site. The site even allows you mobile access, so you can get on it from your Crackberry or mobile phone while browsing at the supermarket or post live from a tasting event.
It's basically bringing wine and Web 2.0 together and does a great job of it so far.
Logabottle.com - Free - [Product Site]