Keeping with the music theme of the day, Mixtapes is a free music app for your Windows Phone that is powered by 8tracks. We mentioned the official 8tracks Windows Phone app earlier (Mango app) and just to cover all the bases, 8tracks is a music site where members can up upload their own music mixes to share with others.
Mixtapes is a Windows Phone 7 app that taps into the 8tracks music mix collection much in the same way as 8tracks does. You can log into your 8tracks account from Mixtapes and the app's layout highlights pages for new mixes, hot mixes, and popular mixes.
You have the ability to filter mixes by tags but there is no genre or artist search or the ability to play music in the background as you'll find on the 8tracks app. You still have the wide range of music that 8tracks offers just in a more basic, scaled down package.
If you're a music fan, Mixtapes is worth looking into. It's a free, ad supported app and you can find Mixtapes here (opens Zune) at the Marketplace.