Race Car Builders: How do I cut plexi-glass cleanly?

[VWAudiPorscheNut at aol.com]

Hey All, I am about to make some 1/4 windows and some lenses from 
plexi-glass... I am curious HOW should I go about making the first rough cuts 
of the pieces?

Jay

1977 Porsche 924 (Wanna-Be Rennwagen, 2029cc, 44mm Side-Draft Mikuni's, 
5speed, Gutted, 2100lbs,Slotted 944 brakes, Autopower Roll Bar, 150HP....)

1988 VegasWagen Jetta GL (1.8L "G" Cam, GLi Front brakes, Rear Disks, 400W 
Alpine System)

1983 Ford Ranger 4x4 V6 (WHAT? a FORD!, sorry, VAG doesnt MAKE a 4x4.)