How to unlock XP2500?

I have the MSI nForce2 motherboard. K7N2G-L with an XP 1800. I'm getting a XP2500 soon.

Anyway is there any possible way to overclock the CPU without unlocking it? I've been a long-time overclocker (don't worry about the warranties I know the risk). I find it annoying I can't overclock even when I downloaded the latest BIOS.

SO are there any guide that show how to unlock XP2500?

www.ocinside.de

As far as I remember that's an nForce2 motherboard soit should be unlocked without doing anything special to the chip.