According to x-bit, Radeon 9800 & 9600 cards that were slated to be released by the end of this month have been delayed, though no further details have been included or confirmed, I'd say the real reason for such delay is that the older line (9700s and 9500s) boards are still selling quite well and at the same time inventory of such boards remains high so they are waiting for those to clear out from store shelves.
Both chips taped out a while ago which discards a problem with production; Radeon 9800s boards are still expected to be available by mid-April while 9600s could be delayed as much as two months...
It is possible that the RADEON 9600-series will appear in some stores in early May or even in April, nevertheless, sources said that single graphics cards in single stores do not necessary mean wide-availability.
RADEON 9600 and 9600 PRO graphics processors are based on the improved R300 architecture, manufactured using 0.13 micron technology, support DirectX 9.0 features and implement 4 rendering pipelines. The RADEON 9600 PRO works at 400/600MHz for core and DDR SDRAM memory, while the non-PRO solution boasts with 325/400MHz core and memory frequencies. Pricing information is still not available.
In case you missed it yesterday, we posted a review/comparison of the Crucial Radeon 9700 Pro and the Sapphire Atlantis 9500 Pro.