overclock 2x1gb 4-Layer V-Data PC3200 DDR SDRAM

[Modjo]

Here's my set-up

Asus A8R-MVP MB
2x1gb 4-Layer V-Data PC3200 DDR SDRAM
Mercury EP-4500 500w (its a lie i tell ya!! ) PSU
AMD Athlon 64 X2 3800+ (939) Manchester Core
AI Overclock - Manual
CPU Freq - 240
PCIE Freq - 100
FID/VID Change - Manual
Proc Freq Multiplier - x10
Proc Volt - 1.375
DDR Volt - 2.7
PCIE Volt - +1.20v
HT Link - 400MHz
DDR Clock - 400MHz

I can more or less get around the idea of o/c CPU but how can I o/c memory?? I'm new to all this (and the forum) and have't got a clue