A new plug-in for Facebook from music player WinAmp may be a long-awaited key to comprehensive music sharing that has been lacking from the site — at least for people who still use Winamp. I am Listening To gives Facebook users the ability to share what they’re listening to at any given time, as well as load playlists directly to their profiles.

The Facebook Listening To v1.0 application updates your Facebook status when you listen to songs with the WinAmp music player. Your Facebook friends will know exactly what tracks you’re enjoying, or you can load entire playlists to share with everyone, marking a big improvement over some of the current options for sharing music on Facebook. The plug-in even has the ability to post your WinAmp tracks when you’re not logged into Facebook. The application is free, though donations are encouraged, and setup requires a special user ID and key code.

There are a few ways to let Facebook friends know about what type of music you enjoy. These are mostly limited to linking to songs in outside sites or programs, like the integration with iTunes, and programs that have offered music sharing directly through Facebook are often short-lived due to licensing and DRM issues. And, recently, Facebook let people send virtual songs to each other through Lala.

While WinAmp has been around for years, its popularity has waned due to more users migrating to players like iTunes and Windows Media Player. If this application can gain a little steam, this integration might help it gain a little momentum.