According to FUD Zilla we can expect the ATI R700 GPU close to Computex, which starts at June 3.
We've seen that many G92-derived products including 8800GT, 8800GTS, 9800GTX and eventually G94 (D9P) – 9600GT who made RV670 runs for the money. Despite that, ATI sold all RV670s it produced in Q4 2007 simple as Nvidia couldn't pump enough G92s. Nvidia cards were faster than Radeon 3870 and 3850, but ATI was a bit cheaper and had a good price / performance ratio.
The new R700 is based on two RV770 chips, and as far as we know in most of the applications, it should end up on average 50 percent faster than RV670. It looks promising and May looks like a great month to launch cards. It will roughly take place one year after heavily delayed and criticized R600 launch. It looks like a nice launch is just months ahead of us.