I using two 3 PAYG sims at the moment. One is in a 3G handset, an O2 Graphite. The other is in my carphone, a 2G handset. This has been working fine, but I got a SMS from 3 about a month ago saying that 'this sim will stop working in this handset after 25th November' (not exactly sure of the date, have to check when back in the car). I got a second text yesterday warning me again that it would stop working. I have not received this text on my other handset, which has 3G. Also if you set the handset to just 3G, you will loose connection most of the time as the coverage is so poor and the handset will not revert to 2G if reception is lost.