Yes, the WebRadio works straight through your 'net connection, no reliance on the PC at all. Same goes for CDDB and the hacks to add weather forecasts and IMDB access.
Biggest complaint with them seems to be poor subtitle support and ff/rw of Divx is erratic to say the least, but not a big show stopper, for me at least. Check out the ez-link PC software replacement it adds loads of stuff not available in the standard server software.
And the latest (2.8.0) firmware update that came out was rubbish for the 508, so I rolled back to the previous one. Seems to have fixed a lot of bugs in the other players though.
Phil