Contact your city's recycling center and ask about a toilet recycling program. If there is one, disassemble your toilet to remove any non-porcelain hardware and drop it off at the appropriate location.
Inquire at concrete manufacturing and recycling companies in your area. They sometimes accept toilets for the porcelain, which can be used as aggregate when making fresh concrete. If they accept toilets, remove the hardware and drop it off.
Call your city's solid waste service provider and ask if a toilet left on the curb will be picked up. If the toilet is damaged, you may want to smash it with a hammer to ensure no one picks it up and tries to use it somewhere.
Take your toilet to the nearest solid waste disposal center if no curbside pickup service is available.