They'll be hitting the market soon. I think the supporting companies get mass packages of chips to include in their new computers soon. Shouldn't be long before thier on newegg.
BTW prices are about $500 for the worst one...the 4200+
and a $1000 for the best one...the 4800+.
I also believe there is a model inbetween as well.
AMD Newcastle skt 754 3000+
Elitegroup 755-A2 ATX motherboard
512 DDR RAM
120 gig PATA Hard drive
128 mb AGP 8x ATI Radeon 9250
300 watt 12 volt psu
Antec SLK 1600 case