The newest cloud-based streaming music service to hit Android is a fine little product called mSpot. At first glance/use, it appears to be much more efficient and stable than HomePipe which you may remember as the first streaming music service.
MSpot does have some nice features, like the ability to limit how much and where it actually stores data on your device plus it auto-updates your collection whenever there is a change.
Free in the market, check it out now. Download link.