Even with iTunes the primary music source, Google has been building on it's own music service. Possibly as early as this fall Google will have a system that allows you to download and stream music. It's been signaled by Google that they want to offer better music support to those with Google's Android.
Top labels would warmly welcome a Google vs iTunes on legal online music sales, as they've tried for years for the likes of Google and Facebook to challenge iTunes. Amazon and My Space, the two other music stores don't have the effectiveness of Google with their web users. Currently Apple is on an iTunes that is web-based, so music and video can be streamed to devices that are web-enabled.
[via CNET News]