The city of Fort Collins, CO, has set up a Yahoo Group for their Leaf Exchange program:

Wondering what to do with all those fallen leaves, or do you need leaves for composting or mulching? The City of Fort Collins offers a web-based service through Yahoo! Groups making it easy to exchange your leaves by communicating directly with people who want leaves or have leaves to give away.

As a courtesy, leaves should be free of rocks, trash, tree limbs, grass clippings and garden debris, and if they’re bagged, be sure to empty the leaves and take your bags back home with you.

Not being a homeowner and thus not responsible for leaf disposal myself, I doubt I’ll muster the motivation to organize something like this in Madison, but I’ll be mentioning it to the homeowners I know.