You must have a SIM card for the carrier you want to use and the phone must be compatible with that carrier.
There is no sim card in Verizon, Sprint, or Alltel phones. The reason is that they operate on CDMA technology which does not require sim cards.
If both phones use the same service provider ( i.e. AT&T ) then yes the SIM cards should be interchangeable.
Cellphones usually have a SIM card. There are land lines that do not as well as Satellite phones also do not have SIM cards.
yes they do all have sim cards also on a different note the t-mobile phones accepts the cingular sim cards when unlocked and vice versa
Cellcom in Wisconsin does not have sim cards, wish they did. I have heard that you can get a sim card from them but non of their phones have a spot for sim cards.
Probably not because Sprint doesn't use sim cards, so you can either get a Motorola Backflip on AT&T (the network it is suppose to be on) or T-mobile because they use sim cards too.
There is no such thing as a CDMA SIM card, since CDMA phones do not use SIM cards.
Yes, Virgin Mobile now uses the sim cards on new phones.
Yes
Not all cell phones are compatible with SIM cards. Some only work with a contract, and you need to unlock the phone before you can use a SIM card.
The iPhone uses the micro SIM card
There are many mobile phones that do not require a SIM card, it depends on the service provider. Any phones from Sprint and Verizon do not use SIM cards.