I read this guide, Activate iPhone Without the Original SIM Card (iPhone 4, 3GS and 3G) | iPhone Activation | iPhoneHeat, which says that I need a "PhoneBook SIM Card" to activate any iPhone without having AT&T. I did some reserach but can't figure out where to buy this type of sim card. Where exactly can I buy a phonebook sim card? I checked walmart and radioshack, but they don't have it.

When I bought a used iPhone 3G, the old owner left his sim card in there. I noticed when I was able to activate any iPhone 3g/3gs with this same sim card.

Will that same sim card from iPhone 3g work on iPhone 4 activation if I convert it to micro sim?