WARNING: Overclocking is not for the faint of heart. Do not attempt to hack your phone unless you understand and accept the risks of turning it into a useless "brick."
The Android v. iPhone debate will continue for some time, but there's one area where Android wins every time: hackability. iPhone users might discuss jailbreaking, which allows--wow!--unauthorized software to be installed.
However, Android phones typically allow everything from overclocking the processor for speed boosts to installing entirely different operating systems.