I ran across this site a few months ago when I was researching some stuff about online music sites, and I was a bit suprised. This site lets you upload your WHOLE collection to their servers, and then streams it to whatever 
computer you want to listen to it on. It was a bit hard to believe at first, but after trying it out and uploading 7,000+ songs to my account it was obvious, they were for real. A good amount of my music was already available on lala so they just matched it and put it into my account for listening without me having to upload the actual file.
The site is just straight hot, just a pleasure to be on. If you have not checked it out I would hop on there and give it a try, especially if you travel a lot and don’t want to lug around a grip of music with you on a hard drive. They have an iphone app, but no android app yet. If you are on there feel free to follow me, search for “tour junkies”. Hope to see you there…