I did mine on boaterexam.com. It was super easy and when your done you get a printable licence right away until they ship you your card. There is an online coupon to save ya ten bucks too,
http://www.tjoos.com/Coupon/100282/BoaterExam.com, i used it and it worked fine you just have to enter the code on the website. The only catch is you need a shaparone for when you do it who is not a relative. If you have a buddy who needs it as well that is the best way cause you can just register each other and get them done in a couple of hours. All the study material is on the website as well so it's just a matter of studying a bit and writing the exam. That is if you need to study, I didn't know anything about boating but needed it to run my pontoon boat with a trolling motor which seems over kill to me but whatever. Good luck!