How to get in and out of kayaks, launch a kayak or get on and off a kayak from a dock, is shown is this video:http://www.youtube.com/watch?v=G7vRwSyV1v4.
This video and article also shows how it is important to select the right height dock - when purchasing a floating kayak dock
All the professionals pretty much agree that the "paddle method" is a very useful and effective way to get in and out of a kayak - HOWEVER - IT ONLY WORKS IF YOU HAVE THE RIGHT FLOATING DOCK.
The dock surface needs to be close to level with the sides of the kayak. When you lay the paddle on the surface of the float - across the sides of the kayak - and put weight on the paddle - it acts to keep the sides of the kayak level. IT CAN'T HELP BUT BE LEVEL.
If the dock is even 5 inches higher than the sides of the kayak - this method will actually tip the kayak!
So purchasing or making a dock or floating dock with a surface no higher than 7 or so inches is the KEY.
One company that designs docks specifically for kayaks and rowing shells is Accudock. www.accudock.com. They even have a kayak slip that surrounds the kayak on 3 sides, and an overhead assist bar that helps in getting on and off the kayak.