Jeff Randall of ESEE Cutlery (formerly RAT) fame wrote something about these over a year ago or so. I don't know if I have that stuff saved or not. However, I have been looking into this sort of thing more and more for emergency gear, disaster preparedness, etc.
"Talk and Toss" Wireless Phones
A couple of these cheap, disposable wireless phones along with a couple Pre-Paid Calling Cards and some Pre-loaded Visa cards - all of which can be purchased at various little shops generally where checks are cashed, lottery is played and Western Union and MoneyGram and Money Orders can be had. In short, shady little places in strip malls that smell like criminality. 8-)