No problem. The base FSB of 266 is also why DDR2-533 memory is what is used for non-overclocked systems, since DDR2-533 is 266Mhz (you might be beginning to see that the actual speed of the memory is the DDR2-speed divided by two). And in overclocking, you raise the FSB by small increments (5 - 40, depends on how nervous you are at the moment). This results in changes in the speed of the memory and the CPU.
That's a very basic explanation of OC'ing to make you more comfortable with the purchases, you'll need to read a much more detailed OC'ing guide before attempting it yourself.