Unlocked Phones come in two types:
1:Unlocked Phones From (OEM's) Or Original Equipment Manufacturer:Phones Unlocked From (OEM ) are Unlocked phones that comes directly from the manufacturer. OEM Unlocked cell phones have never been assigned to any carrier or service provider (i.e. AT&T or T-Mobile). Unlocked Cell Phones from OEM's come in the manufacturer's original packaging (i.e. The Box will be labeled Nokia, Motorola, Sony or any other manufacturer). These Unlocked cell phones don't have any service provider or carrier logos or customization (Internet / MMS settings). Unlocked Phones from OEM can be configured for Internet / MMS settings with any service provider / carrier. These Unlocked Phones have warranties from the country in which they were manufactured. They also usually contain packaging material i.e. manuals, cd and other content in the language of that country. Major OEM unlocked cell phone manufacturer's are Blackberry, Nokia, Motorola, Samsung, Sony Ericsson, LG, HTC, I-mate, Alcatel and Pantech.
2: Unlocked Phones From Carriers or Operators:Phones Unlocked from Carriers are cell phone that were originally locked to a specific service provider i.e AT&T Mobility, T Mobile or any other GSM Carrier Then were unlocked using a code or software. These unlocked phones usually have a carrier / operator customization in the menus and carrier logos on the welcome screen when you turn the phone on as well as on the cell phone itself. They usually can't be configured for Internet / MMS settings with any other carriers / service provider (i.e if you buy a AT&T Unlocked cell phone most of the time you won't be able to set up t-mobile internet & mms setting on it). Carrier / Operator unlocked phones carry local warranty of the country in which the carrier with whom they was originally locked operates. If unlocked without the permission of the carrier the warranty usually becomes void. Again the cd's, manual and other material with these cell phone will usually be in the language of that country.
unlocked cell phones