[FYI] Piggy back SIM works partially
All these people who are waiting and waiting and waiting for the dev team to release something for free - why not put your hands in your pocket and purchase a piggyback sim card, they can be had for as little as £10. We sell them on our website (which I'm not going to mention as I'm pretty much hated around here) for £28.99 but so do other companies - just google "iphone unlock" and find a company which sells piggyback sim cards - make sure they are reliable and you can get in touch with them by either phone or email (and actually TRY to do this before purchase), some scam companies such as iphoneunlocking.com just tie their phone number to a fax machine and most certainly offer no support.
I am only mentioning this to help the people here get their devices up and running, so please don't start flaming.
Regarding the sim cards, I understand a few members of the Dev Team investigated them last summer and came to the conclusion that they weren't great - this was our experience also. HOWEVER - they do work reliably now, there is no longer any need to place into another device to pick up service when you go out of range, the only issue is that on certain networks you cannot receive calls if you have 3G enabled (just disable 3G and only enable it when necessary).
Hope this helps.
Gevey-3G doesnt worked with 02.30.03
I got a Gevey-3G sim. Its worked on older firmware but its doesnt worked with 02.30.03 firmware dont bother buying it people. still screwed.