Same memory for AM2 and Conroe?

I'm building a box end of July/beginning of August. I'm leaning heavily towards Conroe right now, but there's a small chance I may go AM2 (prolly not unless Intel mobos are too expensive. I'd be going either E6600 or AM2 X2 4600+.

So, I wanna buy my RAM now. Do I have to get DDR2-800 PC6400 to work with both?

I also want to OC heavily with which ever proc I get.

Thanks!

I'd say that you would be ok going with slower RAM. It will work on either CPU. However, why not go with PC6400 or faster if you want to OC anyhow?