Highly popular Last.fm launched their official Facebook application yesterday. Last.fm, who was just purchased by CBS for $280 million provides users with an effective way of tracking all of their listening (and now viewing) habits on their computer. These listening habits are used to create an custom radio station that you and your friends can now listen to from the comfort of your Facebook profile. If you don’t already have a Last.fm account, the application will select songs from your favorite music in your Facebook profile and automatically generate a custom radio station. Many were wondering where why a Last.fm application had failed to launch yet. According to the Last.fm blog:

Since the launch of Facebook Platform last Thursday, certain parties have been wondering where our application was. The truth is that we were perplexingly left out of Facebook’s early development program, so while some of our competitors had six weeks to work on their stuff, we had to wait until Thursday like everyone else. The past six days have included 11-hour flights between London and San Francisco, a bank holiday weekend, and some very late nights pulled by our creative/webteam uber hax0rs… but less than a week later we have something for you to play with.

Additionally, new application features will be coming shortly. So head on over to the Last.fm application page and add Last.fm to your profile.