Overclocking an AMD Opteron 170

Hey guys, I'm new to overclocking and was wondering when it is necessary to increase the voltage. Also how do RAM timings effect your ability to overclock your CPU?

I've got an AMD Opteron 170 dual core @ stock of 2ghz.

I overclocked it to 2.3 by increasing the FSB, and changing the multiplier to 10x.

Are there any good programs for checking the CPU temperature?

I ran prime95 for an hour and played a game for another hour, seems to be stable so far. I also did some superpi tests.

I guess I want to go higher and get the most out of the chip. I'm using the stock cooling that came with it but have seen some people go as high as 2.7 on stock cooling. My main concern is screwing something up.

I have 2 GB DDR500 G.Skill Ram. I'm not at home right now but I think the timings are like 3-6-8-10 or something along those lines and a DFI LAN-Party Expert SLI Ultra motherboard.