varies for every chip really, but you should be able to hit 2.3Ghz without too much trouble, What speed grade is your RAM? you should have at least PC3200 if you want to try Ocing much.
The usual routine is to lower your multiplier as low as you can - think this is normally 8x or so, and then gradually increase your FSB in small intervals (2-5Mhz), running some stress testing stuff between each step (e.g. sisoft Sandra's burn-in) - the longer you run it for the better.
When you start getting problems, back down to a lower value that you've previously found is 'safe', and then start increasing the CPU multiplier, again stress testing in between each step. When you start to hit problems, this time try adding 0.05V to your Vcore until it's stable, and carry on..
Personnally I don't like upping the Vcore too much, as it can make the chip warm up a lot, but I would say up to about 1.75V should be fairly safe for a Barton. (some ppl go up to 2.1V and stuff, but I don't feel that's wise unless you have some extreme cooling, and even then it'll shorten the life of the chip considerably.
et Voila! you should soon find the OC limits of your system.
To be completely honest though, you should find you can start at something like an FSB of 190, with a 10x multiplier, and go up from there, to save some time - Bartons are on the whole exceedingly overclockable.
Good luck!
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The end is nigh.. (For this post at least)
