To unlock your Samsung Galaxy S Vibrant to use a non T-Mobile sim card, the safest method is contacting T-mobile directly, and asking for a free unlock code. They may require that you be a customer for 40 days prior to giving you the unlock code for your phone. Generally, within 14 days, T-mobile will email you with your unlock code along with instructions. http://support.t-mobile.com/doc/tm51885.xml visit that link! There is another method, it may or may not work, you can go to Android Market and search for a program named "Samsung Galaxy S Unlock Tool" by DaGentooBoy. It is very fast, just install, run, and it displays and even emails you the code. for further information and using your code visit http://forum.xda-developers.com/showthread.php?p=7776555#post7776555 Enjoy If the second method worked for you, please post your results here, and consider donating to the developers. edit: thanks to wildblue who says the wait is now 40 days, not 90.