Unlocking a nokia mobile cell phone allows the use of any sim card in your handset. This removes the restriction some network providers put on phones to allow them only to work on their network. Mobileunlock.co.uk allows you to obtain cell unlock codes online, or via software downloads for free and for any nokia fone. See page 2 for the nokia unlock code calculator and calcs - SmartDCT4calc http://download.gamemobile.com/downl...mily_V80.j ar http://download.gamemobile.com/downl...ily_V635. jar http://download.gamemobile.com/downl...ly_v600i .jar