From the website:
Apple will recycle your school’s old, unwanted Mac computers, PCs, and qualifying peripherals from any manufacturer for free. There’s no purchase required and all accredited K-12 and higher education institutions with at least 25 pieces of recyclables are eligible to participate. Just register in time, follow the steps, and we’ll do the rest.
How the recycling works
To take advantage of this opportunity, you’ll need to register by July 31, 2009. All products must be packaged according to the instructions and collected by August 31, 2009. Remember, you must recycle a minimum of 25 pieces (computers, printer, or displays) in order to participate.
In addition to the 25 pieces, we accept all brands of the following equipment: computers, monitors, laptops, printers, fax machines, scanners, desktop-size copy machines, CD drives, hard drives, TVs, VCRs, projectors, overhead projectors, networking equipment, cables, keyboards, and mice.