Microsoft in their own words:
Pandora is now available from the Windows Phone Store. Currently it’s not available for Windows Phone 7 users, the app is designed from the ground up for Microsoft’s latest mobile operating system, using the Modern UI design language.
“AD Free, LIMITLESS STREAMING”
Like other Apps on WP8, you can pin stations on your main screen. As per Microsoft, Pandora for Windows Phone includes exclusive functionality compared to iOS or Android, using the Live Tiles feature. The main Pandora tile displays track information for the song currently playing. The app provides full support for Microsoft’s Kid’s Corner feature in Windows Phone, eliminating any trace of explicit content when the mode is activated.
Enjoy the Music !
Note: Users are currently reporting that they are unable to see the app in the Marketplace. This is because, Pandora service is only available in specific countries.