NowPlaying for Windows Phone allows you to tweet or share the current media playing in the Music + Videos Hub quickly to Twitter or Facebook. There are quite a few apps that does the same job, but this one seems to be better. You can even choose from different tweet formats by creating custom formats. The app will also appear inside Music+Videos hub for your accessing convenience. Using trial version you can do all the jobs as a paid version with one restriction of being able to add only one custom tweet format. If you want different tweet formats, then you can spend $0.99 .
Download this little neat app from marketplace here.