ATi's 2400 Pro, 2400 XT, 2600 Pro and 2600 XT are hitting the review sites, and seem slated for an early to mid July release.
PcPerspective
Neoseeker
Hothardware
guru3d
Universal verdict seems to be that the 2600XT underperforms the 8600GT.
The 2600XT is targeted for the $150 pricepoint, even though the 8600GT owns it for $120. The 2900XT is selling for $380 or more, even though the 8800GTS 640MB at least ties it for $340. ATi has nothing between $150 and $380, where the 8800GTS 320MB sells for $260 (and no, DX9 cards do not count anymore).
At this point, I truly do not understand what ATi thinks they're doing. This is a complete systematic failure.