I have CS3 and have been using it since it was offered. The way it works is....if you have CS2, just enter the license # on the install of CS3 and it will work till they release the full (non beta) version.

I havent used CS2 since....despite all the bugs in the bridge and somtimes photoshop will just up and quit on you out of the blue (Memory problems) I just save a lot....lol...the tools are worth it to me....ACR is amazing....and it has the best Pano sticher I have seen to date....and usually works in auto mode quite well.

Roman