I have a microATX case with a 120mm fan for intake and a 80mm for exhaust. The heatsink went on just like any other system I've ever built, and I removed the stock thermal paste with alcohol and applied AS5. The only main difference between my computer and my girlfriend's is that her's has that side air duct for the CPU. Also, because of the small case, my two HDDs are real close to the CPU and RAM.
Dell Inspiron 1501 Laptop
AMD Athlon Mobile TK-55 Dual Core 1.8 GHz
2GB DDR2 Memory
Windows XP Home Edition