heh...we've all been there, man. Yes, that bolt is normal thread, counterclockwise loosens it. The engine turns the opposite direction as the bolt removal direction to gaurantee that it won't back out. Consequently, it's ridiculously tight.

Squirt some penetrating oil into the bolt. Then, you're going to need at least a 2-foot, 1/2-inch-drive breaker bar and a 6-point, 17mm socket. With the car on the ground, hand brake set, and transmission in 3rd or 4th gear, get the breaker bar on the bolt, put a big cheater bar (piece of pipe) over the breaker bar, and pull with all your strength. That should crack it loose.

Put the bolt back in the same way, just give it a good twist with the breaker. Then find a shop, pay em 5 bucks to put your car on a lift and hit that bolt with an impact gun to make sure it's good and snug.