Xyro is correct, you need a custom kernel for overclocking (though, just to nitpick, a kernel is not a driver, but rather the core component of any operating system which handles multitasking, resource allocation, etc. In Android there are still separate drivers, just like in windows, just like Windows has its own kernel).
Unfortunately no kernels with overclocking support currently exist for the backflip. The way Android operates, however, you can still get performance boosts with applications like SetCPU, because by default Android will underclock your device in certain circumstances in order to save battery life, and with these applications you can change the rules or how much it underclocks by. This comes at the expense of having shorter battery life (and the inverse holds true as well; you can sacrifice performance to get even more life from a charge).
Hopefully once Moto comes out with 2.1 and releases the source we'll be able to get someone to compile a 2.1 kernel with OC support (might even do it myself, who knows).