If anyone could code a PPC 2003 app like the Andriod or such that would be great. As you can pick up a Dell Axim for under $100 they make a great remote media player. Use the headphone out to power your stereo or external speakers and you have portable access to your music anywhere in the rage of your wifi or technically over the Internet.
Using the mobile Interface and a third party player works but it's not the best experience. I have mixed results trying to use Opera and the native Subsonic interface vs. the mobile.