I thought that's what you were talking about. Can you do it, yes. Should you do it, probably not. The P4 has a horrible IPC, so even at 4GHz it would lose to a low clocked C2D based CPU. (rev 2 of your board supports those.) You also have to bump the voltage up quite high to get to 4GHz if I remember that article correctly. This means lots of heat, and not a lot of life for the chip. Last, considering you can get an AMD quad for $100, there is no reason to do this assuming your buying new. The article is YEARS old, no one should care about this anymore.
Check to see if you have a rev 2 board. If you do, get a C2D based chip. If not, sell what you have and buy something that does.