How can I unlock a t-mobile razr so I can use my cingular sim card?

You will have to get cingular to unlock it for you normally they will if you just ask

Nokiafree unlock phone codes calculator software (http://unlock.nokiafree.org/)

Nope.. you need the company who's name it is to provide the code
Call up t-mobile and ask for the unlock code for your phone (you might need to giv them the IMEI)

If they try to get out of giving you the code just pressure them because they have to, they just don't want to.