Cheap Unlocked Cell Phones: Switch Cell Phone Providers Without Losing Your Phone

The concept of unlocked cell phones goes like this. Carriers that operate on the Global System for Mobile Communication (GSM) such as Cingular Wireless, AT&T Wireless and T-Mobile use a Subscriber Identification Module (SIM) card. The SIM card is a microchip that stores subscriber data. It is issued by a carrier and provides cell service [...]