Well, in my opinion, if we ever did find out how to time travel, I think it SHOULD be illegal. Besides select people and the person that invented it, they shouldn't make it so that any old person an time travel. Although it may not seem like it, a time machine is a weapon that can be used against ANYBODY ad ANYTHING. Just my opinion. Of course, someone could disagree.
Rules and regulations are definitely a must, but I'm afraid the government would definitely take hold of the technology and would not allow the general population to know about it. It probably already exists and is in full use. No doubt in my mind.