The reports:
IGE:
http://www.civil.ge/IMG2006/IGEReportMissileIncident.pdf (pretty useless report, no names or anything)
IIEG-2:
http://www.civil.ge/IMG2006/MissileIncident-SecondExpertsGroup.pdf (better, but still questionable)
The UN is not in a hurry to investigate, not enough facts supplied by either side.
Of course Russia wouldn't admit, but would it attack that radar site in the first place? Then they would surely have been blamed. So I don't know. If Georgia is making this up, they better get a better commission together to do the report than the current ones.
By the way the report states that the eye witness radar operator did not have any knowledge of aircraft at all, how strange is that!
To me, a probe into Georgian airspace, being fired (or just locked on) by a MANPAD, the Su-24 firing the weapon unguided/unarmed, to avoid dropping it while doing maneuvers (not safe), or just an accidental firing seems most plausible to me. But it seems this version is not thought to be possible by the Georgian. Which kinda figures, because they would have to explain the firing at an unidentified aircraft without proper procedures being done, and leadership structure failing because no permission. This means Russia could have used it to label the fighters in that region as terrorists. And Russia wouldn't admit this either, because Russia would then need to explain violation of Georgian airspace and the accidental firing, which will not be taken up lightly by NATO.
The Su-25 explanation is laughable as well. Then say it was planted and destroyed partially on-site.