Cheers jp. I can confirm it is super fast to change over (like 5 minutes!) & works like a dream
32Gb Black iPhone 4 16Gb Black iPhone 3G on Simplicity, Mio A701 on Orange PAYG, Motorola V3 on Orange PAYG, Nokia 7110 on Orange PAYG, Philips C12 on BT Cellnet PAYG, Ericsson SH888 on Orange Contract
Took 5 minutes here too, have my micro sim ready and activated to put in the iPhone 4 I have pre-ordered from Apple. Not taking o2 up on that crappy early upgrade offer, staying on this tariff for the last 6 months and jumping ship.
It's a shame o2 couldn't take my free minutes and texts off me and give me data instead in the early upgrade offer, its what the iPhone is for!!!
Yes, this is what we are doing, we just aren't snapping the micro sim out of the normal sized sim just yet and have inserted it as a normal sim into our 3GS's and activating it so its ready to pull out and put in the iPhone 4.