The United States Postal Service has partnered with Clover Technologies Group to provide a program that allows customers to recycle small electronics and inkjet cartridges by mailing them free of charge:

The “Mail Back” program helps consumers make more environmentally friendly choices, making it easier for customers to discard used or obsolete small electronics in an environmentally responsible way. Customers use free envelopes found in 1,500 Post Offices to mail back inkjet cartridges, PDAs, Blackberries, digital cameras, iPods and MP3 players – without having to pay for postage.

Postage is paid for by Clover Technologies Group, a nationally recognized company that recycles, remanufactures and remarkets inkjet cartridges, laser cartridges and small electronics. If the electronic item or cartridges cannot be refurbished and resold, its component parts are reused to refurbish other items, or the parts are broken down further and the materials are recycled. Clover Technologies Group has a “zero waste to landfill” policy: it does everything it can to avoid contributing any materials to the nation’s landfills.

It was this philosophy that won Clover the contract with the Postal Service, besting 19 other companies, said Anita Bizzotto, chief marketing officer and executive vice president for the Postal Service.

Apple has offered a similar program for their iPod product line since 2005, and introduced its Take-Back Program in 2006. More info on Apple's program on Apple's Website.