playlist.com like interface

Hi, this is what I want to do:

Easily play music from the "cloud" on my droid X in my car.

I have a playlist on playlist.com that I use on my computer. I would love to access it online but going through a browser is clunky and it stops playing when the screen times out.

I'm looking for an app or a method to play a playlist that is online. Hardware button integration would be great for when the screen is off too.

Anything like this around?

 

try last.fm app - works well on my droid, plays in the background with other apps open, keeps playing when screen turns off, scrobbles your tastes/history, good streams, great way to discover new music, you can make playlists, etc = very cool