Shaun,
If you do not know what you're doing, then I really don't recommend doing it. Like Mikael, I've probably done hundreds of laptop disassemblies and I dislike it (never mind that every time they introduce a new model, they always change how it's assembled and how to take it apart). A can of compressed air works well, although you have to do it in bursts. The liquid that forms on the exit pipe isn't the liquid from inside (that stuff vapourizes in normal room temperature) but is the condensation from the air around it (works along the same principles as an air conditioner....). You don't want that getting into the laptop... if you use short controlled bursts, you can often flush out the dust that has gotten into the heatsink fins, but it can be tricky.
Another solution is to use one of those portable vacuum cleaners that you can find at Costco (search for vacuum and look at the 4 gallon model) or (Never seen them there, but I assume they are) Lowes or Home Depot... the models I am thinking about are sort of like a small toolbox. They often come with some detailing tools to help focus the suction (for places like the crack of your car seat) They are usually powerful enough (at least when they're empty) to suck most of the dust out of it...
As always, if you do decide to take apart your laptop, PLEASE make sure you're electrically grounded. Laptop units (in my opinion) are often more sensitive to static than desktop units.
