More Details Here:
From the article:
Fact is, the RS4 sedan is only going away until after Audi introduces an all-new A4, on which it's based. The new A4 launches this fall and will be sold alongside remaining RS4s (based off the current A4 platform).
The next RS4 will bow at least a year after the new A4-or fall of 2008 at the earliest.
Also mentions that there will only be 300 Cabrios sold in the US.