Force Carbonating PET Bottles

Is it possible to force carbonate PET Bottles (Like these: http://www.mayerscidermill.com/Mayerscm/images/B_plasticBeerBottles500ml.gif ) with a carbonator cap? (Like this: http://www.homebrewery.com/images/carbonatorcomp.jpg ). If so, how quick would it be and what PSI?

My reasoning is that I do not want to wait around for my homebrew to carb and I do not have money for a keg right now.

Thanks for any input.

Hey Scott.

It is indeed possible to do so, and while I haven't tried it myself (I will be bottle conditioning until I can afford kegging supplies), I was actually just looking into this today.

For starters, there is an official product for doing this - here's a good example:
Carbonator Cap | MoreBeer

But, if you're interested in doing this a bit more cheaply, a very ingenious fellow has posted an instructable on how he made a rig using tire inflation valves... very cool!
Home Carbonation System...Cheap, Healthy, and Green.

I hope that's helpful!

Aha, sorry, I see you have already found the carbonator cap. I guess I should have read more carefully. In any case, while I can't definitively answer your "how long" question, the instructable does include a video which I think you may find useful: