GreenPrint World is a free program that allows you to get rid of those extra blank pages and eliminate any parts of pages you don't want all while keeping track of exactly how much you're saving. It also has a built in PDF writer so that you can save things and avoid printing altogether.
This program would be a great complement to the Three Free Tools for Creating, Editing and Reading PDFs and Free Font to Save Ink and Toner that I wrote about recently.
What I would really like to see in the future is a simple desktop publishing program that takes this idea further. Ideally, you would be able to easily cut and paste elements of web pages, documents and your own text together and print and save these creations directly. It's hard to quantify the time, paper and scotch tape wasted when I do this by hand almost every day. Programmers of the world, we need you!