Its highly unlikely that you'll be able to overclock even 1mhz with your current motherboard, for the sake of trying check out the following software:
1)Clockgen
2)Cpufsb
3)Softfsb
and please dont blame me for any damages..
P.S I have OC'd my system almost 100% and havent installed any extra cooling depends on the cpu, if you have an old P4 then you have to keep in mind the heat issue even with minor OC'ing.