okay man, I know you want to be stealthy so...the um...window police don't get pissed about you breaking your windows...

so, you need
1 glass cutter
1 roll of duct-tape
1 putty knife (or something like it)
1 pair of gloves

now, glass cutters don't work like that shit in movies where they cut all the way through, they're for scoring the glass. So, cut a line down the middle of the window, then layer duct tape over that cut in the middle. Then use your putty knife or similar instrument to pry all of the caulking and black sealant shit out from between the window and it's frame. Then, with a sharp motion, strike the glass breaking it in the middle, but because the duct-tape was holding it there will be little noise. Then just remove the pieces at your leisure. If you think you'll have trouble getting those two pieces out, you can always cut it into fourths when you make your first cut.

also a much easier method like infinite's but without any room for error, is a loaded center punch...push it down on the corner of the window and watch it spider our and fall to the ground, very quiet. And if the window that's troubling you is on your car, this is the best method for that.
I am the Lizard King
I can do anything