First question, what is your motherboard?
Next question, how fast is your RAM?
The first thing you would do is go into your bios and increase the bus speed (usually found in Advanced chipset settings). increase it by 5mhz at a time until your system crashes. Then back it off a few mhz. You'll probably want to increase your Vcore voltage by about .5v or maybe more. Once the system seems stable run a program like Prime95 or CpuBurnIn to really test the stability.
You will have to constantly monitor your cpu temperature, MBM5 works very well for this. At 60C you are seriously redlining and should consider some better cooling.
This'll get you started and you'll find tons of info here and on other overclocker sites.
Just remember o'cing is hazardous to your system and will void any waranties.
C.
XP2500 oc'd to 2.2ghz!