If you find yourself climbing an extension ladder often, you might be interested in this build your own ladder pony. This is like a three legged platform with wheels. You can load you supplies or tools onto the platform and then once you are up the ladder, you can use the pulley system on the pony to haul up your tools or supplies.
This is really nice if you spend a lot of time adding tar to roofs as you can haul a five gallon bucket up on the pony instead of trying to climb the ladder with it. The instructions are by Uncle Sam and you can find them on Instructables. He mentions some uses for it and I like the one about how you can haul stuff up to your boat deck if it is docked on dry land.
If you read the comments on it, one person mentions a way to add a tire and be able to haul things right from the truck. Another comment I really liked was from someone a little older who said they were going to use it on their basement stairs to haul bags of salt and such. That would be a neat way to avoid hauling them down and up the stairs.
Read more>>>>> http://www.instructables.com/id/Ladder-Pony/