I did on my older MacbookPro5,1. It didn't even seem like I dislodged much dust, but it made a huge difference. Now the fans don't go above 3-4000 rpm even with the cpu pegged, which is quiet. Before it would consistently spin the fan at max speed even with modest cpu use. This old beast is far quieter under load than the new MacBook Air 13" I had for a week and returned.

I'd suggest downloading smcFanControl. That's what I use on my MB Pro, and it works well. You can set different modes that will keep the fan at or below a certain RPM. If I'm gaming, I let it go up to 6200 rpm. If I'm not doing much (like now, just browsing on the internet and maybe running a couple other programs) I drop it to 3000rpm. That usually puts me around 45* C and keeps it nice and quiet. Then I've got a middle setting at about 4200rpm that makes some noise, but isn't quite as obnoxious as full throttle.

+1 from me: smcFanControl is seriously handy if you do any sort of coding on a macbook. Was recently running a genetic algorithm on it and the app allowed me to bump the fan speed up to something ridiculous in order to keep the cpu at a comfortable temperature. I also tend to raise the speed if I'm watching flash video, since that's still ridiculously cpu intensive on a mac...

Yup. Last time I opened it up (to replace the optical with a second SSD), I placed it electronics-down over open space (propped an edge against the table, held it up with a hand) and air-canned all the crap out of it.