Orange UK have launched animals name tariffs on PAYG, which they've had on contracts for a year or so.
http://shop.orange.co.uk/shop/payasyougo
The option called Camel has cheap international calls to more destinations than Call Abroad, and some are cheaper now. USA and Canada are 6p/min, while several European mobiles are 10p/min, which seems unbeatable to me for direct-dialled calls (unless using the bundle option on O2 payg). UK calls are all 20p/min (undercut by the 15p Raccoon tariff)