I have a 3gs iPhone which is jailbroken and unlocked so I could use a pre-paid SIM card when I moved abroad. I was backing it up through iTunes until my personal computer was stolen. Now I have re-downloaded iTunes on a new external harddrive via my work computer and want to back up my iPhone but am afraid of erasing data in the process and want to maintain it as jailbroken and unlocked. Any advice? Thanks in advance.