is an Open Source utility to keep track of your Xbox Live friends on your Mac. You can set it to let you know when your friends log on via a Growl notification (so you can get fragging as soon as a buddy shows up online). Unfortunately, according this review
MacLive is still a little rough around the edges, as the add a friend feature is apparently broken and there isn't yet a way to send messages, manage the friends list, etc.
Nonetheless, this is a great idea, particularly if the developer James Howard continues to improve it. MacLive is a free download
at Google Code.Thanks Peter!