According to DigiTimes, mainstream GF106 and entry-level GF108-based graphics cards will hit around July and August, respectively, for $180 and $100. That's quite a bit higher than early predictions suggested. Unfortunately, no other details are available regarding specific models or what to expect compared to their more expensive counterparts.
Meanwhile, the GeForce GTX 460 purportedly debuting in June will use the new GF104 Fermi architecture and should feature 256 shader cores, 64 TMUs, 32 ROPs, and a 256-bit memory bus. Other cards expected to use the GF104 core include the GeForce GTS 450, 440 and 430 which should cover the $180 to $300 price range. Of course, none of this has been confirmed by Nvidia for now, so plenty could change by the time these cards are actually out.