The last revision of the prototype chip – upon which a certain “pre-review” is based – also suffers from problems which are serious enough to get another re-spin, sources tell me. This re-spin puts a hold on the launch for another couple of weeks, and now R600 is looking like an early March launch, probably the week before SnowBIT in Hangover. However, AMD/ATI is making severe changes to the whole line up and we can say that this launch, when it happens, will be very, very shocking for the 3D industry.
AMD R600 Chip Pushed Back

I don’t think this is a suprise to most of us, but the Inq is reporting more info stating a March release for their DX10 GPU.