Skatter Tech has a pretty nifty tutorial for PSP owners with 2.60. Using iTunes-PSP-Server.exe, you can stream your entire iTunes library over wifi using the built in RSS functionality. The requirements include:
- PSP With Firmware v2.60
- Networked XP Home/Pro Comp.
- WiFi (802.11b) Network Router
- Apple iTunes v6.0.4 Installed
- Songs in iTunes Music Library
- At Least 1 Playlist With Music
If you have all those things, have fun streaming! From what I read, the process is pretty simple and the results are quite rewarding.