RAM Question

I've seen people talk about the PC4000 type of ram. Are those compatible with regular motherboards? What about the ASUS A8N-SLI Premium? Is getting the PC4000 a advantage compared to a low latency PC3200? Or wait for a even lower latency verison of the PC4000

Yes, a motherboard that will run PC3200 will run PC4000. Check out this thread for a good speed vs. latency comparison.
http://forums.anandtech.com/messageview.aspx?catid=28&threadid=1475190&enterthread=y