Unlocked Galaxy i7500, Reset Will Remove it?
According to the FastGSM page: "Congratulations! Your phone is permanently unlocked and can use it with different network SIM card. It will never relock again even if you do software update." (source)

This means that even a factory reset won't relock the phone. I assume this is because Samsung phones use the /efs partition to store the IMEI and other network data, and the unlock modifies these files. The partition is not modified by updates/resets.