Theres very useful guide for overclocking intel duals and quads on top of this section so i guess you should read it first, plus the guy who made this guide is using (i think)p5q dlx, so bios and its settings will be almost identical(dlx will have more options i guess). it explains all the basics, so - read it first, ask questions later
When you set fsb in bios you have ram speed as well with various speeds to choose from and they change too as you change fsb, so take as close to 800mhz as possible. I have the same ram but 2x1gb and it can go up to 980mhz but generally if fsb/ratio can give 800 than you should go for it. The cpuz reading on the first stick is weird but i cant really help you on that,maybe someone else can. Try swapping sticks in slots and check if it comes like that again? Did you test it with anything like prime95 after oc?