The gang at HardwareSecrets have just published an article that will hopefully help decode all of those memory timing settings. Knowing exactly what all of those settings mean is going to become increasingly important with the move to DDR2, & eventually, DDR3.

"Timings are numbers like 2-3-2-6-T1, 3-4-4-8 or 2-2-2-5, the lower the better. In this tutorial we will explain you exactly what exactly each one of these numbers mean."