A laptop is not exactly the most mobile of personal music players, but now with Pandora music it's at least a very personal way to listen to music on the go with any broadband connection.
From the site FAQs here is a description. "Pandora is a music discovery service designed to help you find and enjoy music that you'll love. It's powered by the Music Genome Project, the most comprehensive analysis of music ever undertaken. Just tell us one of your favorite songs or artists and we'll launch a streaming station to explore that part of the music universe."
I was a little skeptical when I gave it a try, but was amazed to find that it really works well. No commercials yet, but they are coming. You do have the option to subscribe for a commercial-free experience at a cost of $12 quarterly (i.e. for 3 months) or $36/year.
If you put in "Let it snow, Let it snow, Let it snow", for example, then it will do a Christmas theme. You get to pick the version of the song you like and it will generate a custom station for you.
I tried "Carpenters" and "Dean Martin" and sure enough it came back with music I loved, both from known artists and ones that I've never heard of before. You can continue to fine tune the choices by giving a thumbs up or down to what you listen to, and you can (with some limits due to contractual obligations) pause or skip forward to the next song if you don't like the one that's playing.
It's only available in the US right now, but is a very impressive service. I don't see any signs of support for pdas yet, but you only have to be Flash 8 or 9 compatible, so I suppose a wifi Pocket PC will be compatible as soon as the current version of Flash for Pocket PC rises to 8 or 9.
You can try it out for yourself and make your own streaming radio station at
www.pandora.com.