Mike,
Looks like there is a good supply of the 2.8 GHz parts, both FX and Opteron. The highest bin tend it to be thin at times.
Also, only the highest bins of Opteron seem to be available. I think AMD wants the stock of 130nm parts to completely drain before releasing lower clocked parts on 90nm.
Also, (unless I missed it earlier) distributor #2 now has X2 4200 and 4600 available.
Joe