If you do for Celeron, it will be no problem. But I doubt any performace mprovement if your P4 is real P4 not P4 Celeron. You can check out Ebuyer and overclockers
If you want realy P4, you may not able to find anything because your motherboard may only support "old" Northwood P4, not "new" Precott P4.
It is almost impossible to find any Northwood P4 now. So you need to go to your motherboard's manufacturer's web site to see if it support "Prescott"