If you have the room in your backyard, consider creating a compost pile from the leaves you rake up during the fall. This natural compost can be used as fertilizer in the spring for your various lawn and garden projects. This is a natural source of fertilizer and a way to save a few bucks for the next year on gardening costs.
Run your lawn mower over the leaves to cut them up in smaller pieces. Rake them up into a pile once the leaves start turning brown. You might want to bag the leaves because you may not be able to use compost them all at once.
Mix the existing soil with the leaves as well as other organic food waste. It is usually a good mix of carbon and nitrogen materials that make good compost. If you have too many leaves, you can still build a leaf pile and mix in a layer of dirt between the leaves.
Here is a good video from Howcast that shows you how to do it.