Memory will be fine for you to start overclocking with, you just will have to use a 1:1 memory divider ia all, at first your memory will be running underclocked, but the closer you get to 400 fsb the more it will be close to running at stock.
Now the fun bit, most memory will run a bit over stock, some not a lot some insanely higher, so thats where a lot of tweaking and testing comes into it, but hey thats the fun part right lol.
So basically you are fine upto 400fsb (1:1 divider) anything over that well its pure luck on both mobo and memory.