Sirius XM Radio Inc. released its long-awaited iPhone application for free today.

The free app allows users with an Internet subscription to Sirius to listen to online channels via the popular device.

All channels for which the Sirius has mobile performance rights will be available The company has 120 online channels including MLB Home Plate, CNN, Martha Stewart, Opie & Anthony, Sirius NFL Radio and other programs.

The Sirius XM app allows new and existing subscribers to access great music, talk and sports almost anywhere they go. For millions of users, the best radio on radio is now the best audio content on their iPhone or iPod touch, said CEO Mel Karmazin.

The new app also allow end-users to purchase a song directly from the iTunes Music Store, check what is playing on all 120 channels at any time.