From the Summer 2008 edition of "Pawprints" - the newsletter of the Peoria Humane Society:
You can now sell an item on eBay and donate some or all of the selling price to the Peoria Humane Society to benefit the animals. Through eBay Giving Works, you can list your items on eBay and donate from 10 - 100% of the proceeds from the sale to the Peoria Humane Society. Your items will appear with all other listings on eBay, and feature a charity ribbon and information about PHS so buyers know that you and they are supporting a good cause. You complete the transaction as usual, but MissionFish, the dedicated solution provider for the program, will collect the donation from you and pass it on to PHS. Go to ebaygivingworks.com, and they will walk you through the easy selling steps.
Another suggestion: cut out the Ebay and shipping expenses, go to the Peoria Craigslist.com, and list your item there. A Craigslist listing is free and easy. I can help you if you need it. Then write your own check and send it or deliver it to the hardworking staff at PAWS yourself. You can specify how you want your donation spent. I always asked for it to be used on the personal comfort of the animals - Kong toys, dog biscuits, sleeping mats, etc., but there is also a big need for spay/neuter clinics, public education and so much more.
This is a great way to assist in managing the Peoria County pet overpopulation, particularly if there is no room in your home for pet adoption. Give it a shot, then report back here. Guaranteed to make you feel all warm and squishy inside.