I use pretty much the same method as sswilson.
I put an extremely small amount on the heatsink and work it in with some plastic wrap on my finger (you should still be able to see the metal of the heatsink through the thermal grease).
Once it looks like i've filled in all the imperfections/tooling marks I put another small amount on top of the CPU and spread it out with a credit card. I usually spread it out until I can almost see the heat spreader, basically it's a micro thin layer.
Then make sure you place your heatsink on CPU squarely and clamp it down and you're good to go.
I honestly don't normally go through this much trouble for a normal build, but if i'm going to overclock then I will.
