Great news for those how like to root their phone and flash custom ROMs out there. Now the T-Mobile Samsung Galaxy S II can be rooted and the process is very easy. Here are the instructions:
1. Make sure windows recognizes your phone in ODIN.
—- adb reboot download
-or- Turn phone of, and hold both Vol up + Vol down, and plug the USB cable in.
2. Select the PDA button and browse to the recovery-cwm-hercules.tar
3. Select Start
4. It should flash the file to Recovery and reboot the phone.
5. After it has rebooted, mount USB storage and copy the Superuser zip to the sdcard
6 Reboot into recovery
— adb reboot recovery
-or- Power off phone, unplug USB, Hold Both Vol up + Vol down and Hit power
* PERFORM NANDROID BACKUP *
7. Select Install zip from sdcard, choose the superuser zip and let it finish.