id be holding off on realeace to see what happens with vista and direct x 10,
Here's a hint - nothing will happen. I don't know why people keep bringing this up. Since OGL is tied to your video card manufacturer's drivers (ie pretty much only ATI or nVidia support it) Vista has EXACTLY THE SAME OGL support as XP does, assuming the vid card manufacturers bundle more or less the same OGL drivers, which is certainly the case as of Vista RC2 and nVidia.
Surely there must be some big betatesting which the community knows about before any release at all
There will be some small testing procedures within BRL, but if past history has told us anything then most of the testing will be conducted after releasing v1.0 to the public. It's the only realistic way a small company can test thousands of different hardware setups.