So far I'm hearing that Groove is the replacement and yes, it's not WMP or WMG.
As to the radio stations you should be able to hit them up in a browser. My stations have this feature.
Windows Media Guide is Music they say they are retiring it at the end of June anyone know what Microsoft is going to do in it's place. There are many great radio stations on that link including two of mine.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic