Well, this isn't specifically for a PSP, but I bought mine a few weeks ago from Buy.com with a 5% off coupon that's floating around. $8.50 off is better than nothing.
I don't think you're going to be able to find any substantial discount on a PSP 2000 when the 3000 comes out. At least, I don't remember that happening the last time around. I think most places just kept on selling the 1000 at the normal price until they ran out, then restocked with the 2000.