Most seed companies will give out free catalogues from their site. My favorites include Seed Savers Exchange, Baker Creek, and Vermont Bean.
Here you can see the seed order for our greenhouse last year. All heirlooms:
This is one of three websites that I have been developing over this past year in a Garden Curriculum Toolkit focused on middle school and high school students.
This material including an 80 page handbook, 6 garden videos, a soil testing kit, and an array of materials will be ready in the January in a portable waterproof briefcase. There are all sorts of wonderful links at http://healthycamden.blogspot.com/ check it out.
Additionally all of these materials will be available on a USB flashdrive.