Newegg has the 8600's, but they have yet to update the power seach page, or add them into the categories in any way. the only way to get them is to view the deals, or to search
the 8600Gt and 8600Gts both have 256 ram, all is GDDR3. the only difference is the clock speeds. The GTs is on average, $199, while the gt is on average $169 (only 3 models, the XFX appears to be the best, and closest to a gtx)