How to tell memory speed?

I am fairly new at this OC thang, and i want to know where i can display my pc2100 mhz? and also, how to overclock memory? i know about timings and such, but how do you actually put more voltage into memory and up the clock on it?

the 2100 is not mhz but bandwidth, ie 2100 mb/s. To up the memory speed you must only raise the fsb in the bios, same for voltage if your motherboard support it. As for speed tests SiSoft Sandra works well for comparisons.