Google `absolute radio listen on your computer`

Click on the ogg links *if* you've added OGG support, otherwise click on the MP3 stream that you want. I've got them all bookmarked and listen. You'll need to know that in the evening UK time their servers do tend to get busy and are hard to get a connection sometime.

And the link, in case you don't feel like googling...
http://www.absoluteradio.co.uk/liste..._computer.html
(follow that link with your n900, click on the appropriate link, once it's playing add it as a bookmark)