1. Turn on the HTC MyTouch 3G. Dial *#06#. The phone's 15- to 17-digit IMEI number should appear in the display. Write it down. 2. Switch off the MyTouch 3G. 3. Hold the phone face down, right-side up in the palm of your hand. Firmly press down on the battery cover to release it from its lock, then lift the cover off. Remove the phone's battery. 4. Use your thumb to slide the currently installed SIM card out of its slot. Be careful not to damage the gold contacts on the front of the SIM card. Store this SIM card inside of an envelope for safekeeping. 5. Insert the SIM card issued from an alternate GSM network carrier into the SIM card slot. Position the SIM card so that the gold contacts are face down and the chipped corner of the SIM card is located in the top-left corner before sliding the card into its slot. If you don't yet have a SIM card issued from an alternate GSM network carrier, just leave the slot empty. 6. Compare the IMEI number printed on the label inside the phone's battery compartment to the IMEI number taken down in step 1 to verify that it's correct. It's important that this number is noted correctly. 7. Reinsert the phone's battery and put the battery cover back on. 8. Use one of the SIM unlock services listed in Resources to order the SIM unlock code for your HTC MyTouch 3G. You will be prompted to enter the current service provider for the phone (select "T-Mobile), the phone's model (select HTC MyTouch 3G), and the IMEI number unique to your phone. Once the order is complete and you receive the unlock code for your phone, complete the remaining steps. The unlock code you receive is unique to your specific HTC MyTouch 3G, based on the phone's unique IMEI identifier. 9. Turn on the phone. Wait for it to power up. "SIM network unlock PIN" should appear in the phone's display." 10. Enter the SIM unlock code for your phone. Select "Unlock." If the correct code was enter properly "Network unlock successful" should appear in the phone's display. Your HTC MyTouch 3G may now be use with a SIM card issued from any GSM carrier.