Hi I need some advice. I currently have a 3G with firmware 3.0.1 (have been using it to tether) and would like to jailbreak and retain ability to possibly unlock. I plan on updating to a 4, so I would like to play with this one in the meantime. What is the best way for me to proceed? Which tool should I use? How difficult is it to reverse the jailbreak if necessary?

Sorry for the newbie questions and thanks for all the help,