XM + Napster Beta has been released! You can try out the 14-day free trial, but note that you must be an XM Radio Subscriber to use the service.

The XM + Napster full service costs $9.95/month, while the XM + Napster Light follows the iTunes model of $0.99/song. Both options give you access to the full 1.5 million songs.

UPDATE: From the press release, XM + Napster allows XM subscribers to listen to more than 70 XM music channels on XM Radio Online and access Napster's catalog for on-demand listening, purchasing, and downloading. The service seamlessly links XM subscribers to Napster to instantly find songs played live on XM by its world-class DJs, get in-depth information about artists, and discover new music and old favorites through customized music recommendations provided by Napster's professional music programmers.

Neat.