It can be done.. In many cases it is easier than AMD, but you must have good components!!
Intel runs hotter than AMD does and relies on the Mobo / RAM greatly.. You cannot change the multiplier on an Intel though, they are locked from inside the processor (if I recall correctly), and it gets set on every bootup.. You can only increase the Front Side Bus speeds to boost speed.. The up-side to Intel is that if you clock out your RAM, you can change to a different CPU to RAM ratio.. So, instead of 1:1 (200mhz / 200mhz), you can go 1:2 (400mhz / 200mhz)..
Make sure that your friend has a mobo that can support the higher fsb speeds (northbridge / southbridge), appropriate cooling for the cpu / nb / sb / ram, and quality ram in his system...
EDIT: I believe that AMD started working with ratios as well back when SocketA came out

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