We created something we're calling Kegberry. It's a way to monitor your keg taps and display them with a web interface, using none other than the Raspberry Pi. Here's a screenshot:

You can use the monitoring features to know exactly what is being poured and how much is left -- or use it without monitoring as a simple digital tap list and keg management web server.
We put some instructions together along with a ready-to-go system image here: http://kegberry.com/ . Under the hood, Kegberry is running Kegbot (http://kegbot.org). You can see a demo of the admin interface here: http://demo.kegbot.org/ .
Of course, it's all open source and free, and we hope and encourage developers to build on top of it! And though we recommend a special controller board for some of the sensing features, we're also adding support for the Raspberry Pi GPIO any day now. Check out the FAQ for some more detail.
We know there are still a few rough edges, so we'd any feedback from intrepid early testers! If there are any questions here, I'll be happy to answer them. Thanks!
mike (& the rest of the Kegbot crew)