There seem to be a few overclockers in this thread and a few others who seem interested... For those interested, here is a quote from overclockers.com to clear up some confusions on the current P4 designations:
"Quick Intel Scorecard Intel's doing a pretty good job of confusing people, too:
If it's 2GHz or less, and doesn't have any letter following the number, it's the old generation Willamette.
If it's 2GHz or less, and has an "A" after the number, it's a Northwood set to 100Mhz FSB.
If it's over 2GHz, and doesn't have any letter following the number, it's a Northwood set to 100Mhz FSB.
If it's over 2GHz, and has a "B" after the number, it's a Northwood set to 133MHz FSB.
There are no 2GHz or less GHz "B" chips, nor any over 2GHz "A" chips. "
The sweet chip for overclocking right now looks to be the P4 1.6A. Right out of the box, my P4 1.6A did 2.13Ghz. With some voltage tweak and better heatsink/fan, I am now running 2.4Ghz for a total price(including bigger heatsink/fan) less than cost of a P4 1.8A. Some extreme overclockers are crossing the 3Ghz barrier!