It looks like Google Music and Myspace-backed Lala.com's streaming music app might beat Spotify to the US iPhone.  What is Lala?   From TechCrunch:

Lala revolves around the concept of the ‘web song’ — you’re allowed to listen to any song you want totally free exactly once. If you like it, you can then pay 10 cents for the right to stream it as many times as you’d like from then on. This means that you can ‘purchase’ and entire album for around a dollar. You can also use Lala’s Music Mover tool to upload your entire library of MP3s to the cloud free of charge. This is all built on top of a very slick interface, but so far it has come with one downside: because all of the songs are streamed, users didn’t have a way to access them when they weren’t at a computer. Lala’s iPhone app changes that. [it also has a smart caching service that caches the most important/recently added songs.

Interesting concept and a direction which many predicted Apple would head.  It isn't approved yet and we know anything can happen until then.  Check the video below to see how it works.