Pretty recent news.
Report: AMD to Release 28nm GPUs Before Nvidia
Southern Islands code name for AMD's 28 fabrication is due out about November 2011. Kepler to be out by Feb 2012 by both companies suggestions to news sources. No solid time frame.
it seems that 28nm yields are still low and AMD will be delayed even futher which might put it closer to Nvidia's release time frame.
So history is repeating itself like the first gen of 40nm fabrication chips did with major delays. If your thinking of buying a new card and have been waiting it seems your wait is going to be much futher than first anticipated.
Another article talks a bit about the actual fabrication actually going on which came out July 6, 2011.
Report: AMD could beat Nvidia to the punch with 28-nm GPUs
"Southern Islands is more or less a play-it-safe shrink of the Cayman design that powers the Radeon HD 6900 series" also continues to say "Kepler is a new architecture with substantially more processing resources than Fermi. Word is that Kepler is "heavily skewed" toward compute applications, as well, yet its power management capabilities aren't up to snuff."
Hope this helps you decide to pull the tirgger or not on your card now or wait it out and hope it's on time. I wouldn't hold my breath.