Right - had an activated O2 micro sim for my iPad which I'm not using - moved to VF, and a non activated O2 PAYG full size sim. So, checked the new PAYG worked but didn't add credits. Went through the online O2 conversion to Micro SIM process and after about 8 hours, PAYG full size sim stopped working and the Micro SIM now works in a standard handset with a convertor as a PAYG voice sim. I've topped it up and everything works. Apple have apparently said you can't use micro sims between iPad and iPhone 4 which is probably true - not interchangeable as in swap back and forward but the hardware is clearly the same. So you guys who have simplicity and an iPad micro sim, go for it. It should work. Doesn't mean that O2 won't still zap the sim if they only want iPhone contracts in iPhone 4.