Well most of the sites I've seen almost never list a release date. The best bet is to start looking around at places that sell the stuff and they might have a release date otherwise wait until you see a press release or something saying that whatever is now out
the AMD 2600xp is already out. do you mean the 2800xp? the 2800xp is supposed to be avaliable in jan 2003, and the 2700xp is being released in november or december, i think. here is a link to a site that has the 2600xp for sale.