Qualifications
Ever wonder if all those certificates and degrees you see hanging up in a lawyer's office are real and not just written in illegible font? Well, turns out they're real...and you'll have to get one of each for yourself.
You'll have to spend four years studying as an undergraduate before you can apply to law school. But you can't just rest on your college career, SATs, APs, and/or OMGs. You'll have to do well enough on the LSAT to prove to law school admissions personnel that you've got the right mind to mold into a lawyer (source).
After you get accepted, you'll do three years of law school, pursuing a Juris Doctor. After that, if you want to go aboard the lawyer-ship, you'll have to apply for admission to a jurisdiction's bar examination board, which requires a background check, complete with rectal thermometer, passing the Multistate Professional Responsibility Examination and the, anyone?, bar exam.
When you pass that gauntlet, there's the oath of loyalty to the Constitution, and traditional mud wrestling. Then you have done everything you need to lawyer...except learn how to do it (you'll learn on the job).