Calling all kayakers!
They didn't even give lessons where I rented from. They just handed us a paddle, told us which kayak was ours and in we went. Now that I'm thinking about it, they probably should have given us lessons when we rented the kayaks. 
We did start on a small lake, so perhaps that is why we didn't have lessons?
BUT-- it's a LOT of fun! I hope that you enjoy yourself-- I know I certainly do! And I will echo the above poster's sentiment to remember that you have to paddle back. :)
Very carefully! 
But on a serious note, we were on the shore the first time (MUCH easier). Start with the kayak perpendicular to the shoreline, with half to 3/4 of the kayak in the water depending on depth (enough so that you can push off, but not so much that it floats away on you). You just get in standing up, sit directly down, and then push your kayak forward into the water.
Dock is a bit more tricky. You sit on the dock with the kayak parallel to the dock, put both feet into the kayak, keep your hands on the dock to stabilize you and sit your butt on the seat as quickly as possible (but not too quickly that you rock the kayak). It really helps if you have a friend to hold your kayak.
I've done kayaking and rowing, both are VERY fun. Rowing is really nice if you like a team component, and they help get you into shape from the ground up. You could literally walk in from the street and learn to row, get fit (or more fit), and make a lot of friendships. (Just a thought, because our boathouse lets us take out the kayaks with the cost of our rowing membership--so you get the best of both worlds! )
