I recently released a free application for WP7 called Searchler Music Video Search. It allows you to enter an artist, then from there you can generate a music video playlist of their top songs, similar artists (like Pandora), or albums and watch the videos inside the application with an in-app player. You can even pin your favorite Searchler searches.
I also developed a companion website for the app @ http://searchler.com If you share an artist within the WP7 application it will create a link to searchler.com where your friends can also view videos of the artist.
The app will automatically find new releases and allow searching of new artist without need to update. It can find very obscure stuff surprisingly well.
Also, I translated the app with Bing Translator service to the following languages: English, Portugese, Dutch, Finnish, French, German, Japanese, Russian, Korean, Spanish, Italian, Greek, Polish, and Swedish
^(If you speak any of these languages and know an error in translation please message me and I will make sure to fix it in the next update) Please let me know what you think!
Below you can watch a video of the app in action and grab a link to download the app free in the WP7 marketplace!