Mattel, the makers of Barbie dolls, Matchbox toys and MEGA toys has started up a recycling program. If you visit the Mattel Playback site, you can print off a free shipping label and send them your outgrown toys for recycling.
This program is just launching. It is currently only available in the United States, Canada, France, Germany and Britain. People in other countries need to ride around in their Matchbox cars a little longer.