This Yahoo! Pipes pipe will look at the rss feed for your gamertag from 360voice.com and spit out just the entries where achievements occoured. And it will filter out weekly recaps. This is not an original idea, but it worked out well. And I set up the pipe to accept easy input of your gamertag to use. It is good for places on your own site where you want to bring in a feed of your XBox 360 achievements.
It requires that you are registered with 360voice.com.