I just installed Rygel and it shows up in Windows Explorer.
But as an Other Device rather than a Media Device.

Also, in XBMC media center, I can see the N900 with folders (video, pictures) but I cannot get into those folders.

So it's not working for me. MediaTomb is a way nicer solution, except it doesn't work for me either. :P Segmentation Fault is what I get when adding media.