Your friend is correct. When intel manufacturers their cpus, the processors are rated and given a certain clock speed rating. Usually there is a lot of head room with these ratings.
On the PC side of things, most overclocking is done in the pc's bios. This is the very low level settings of the computer. Apple's new intel computers do not use bios and instead use EFI. This means there is no overclocking via the bios. I also do not know of any solutions that exist to overclock from within os x and windows programs probably wouldn't work either.
In short, its probably not possible. And its not really a good idea to do this with a laptop form factor. Overclocking your mbp will just make it hotter than it already is and no one wants that.