MacLive is a new open-source app for the Mac that enables Growl notifications for your xbox live account. Very cool! The interface could use some work but it does what it says fairly well — you can even choose to only receive notifications about certain friends or specific games.
Take a look if you're the adventurous type — it's very pre-beta at the moment but I'm sure that with the attention it's getting now development will speed along soon.
via 99Lives.org