one ring phone scam

There is a phone scam going on that is racking up huge charges on cell phone bills.  They call it a "One Ring Phone Scam".  A phone call comes in, usually only rings once then the caller hangs up, and it shows up as a missed call on your phone.  You call it back, and you're slapped with international phone call charges.  I mean charges to the tune of $19.95 just for calling, and an addit