I want to say thanks! to all who have been posting on this forum, it helped a lot as I was trying to get Allshare working on my BD-C6500. I could never get PCSM 4.x to recognize the device; version 2.3 recognized it, but still didn't work right. I tried serviio and had some limited success with it, but not a lot and not without some work I didn't want to have to put in. I also tried Mezzmo and it really worked well "out of the box" but I didn't want to pay for it.
What I would like to say to everyone has been said before, but not with (I think) enough emphasis:
The DLNA server in Windows 7 Windows Media Player works beautifully, with no additional software required. Just add the media to your library, enable streaming to your network devices, and it works. The device appears on the BD player and the media is available. No PCSM, no serviio, nothing else required. If you're considering moving to Windows 7 (which is excellent, BTW) then this is another reason to do so, and I DEFINITELY wouldn't pay for any software to do this; just add the money to your "saving for Windows 7" kitty.
It won't allow me to post an URL, but you should be able to turn this into a link that helped me configure Win 7 to make this work:
The only problem so far is that I can't see MKV files, which I don't think Windows Media Player supports, but I don't have a lot of those files anyway.
[edit: This link leads to software from a reputable source that enables MKV playback in Win 7 MP: labs.divx.com/mkvwin7preview