I had a single page reference card (plastic) for the 6502 that had everything you needed to know on it -- it was awesome! It was used many times while hacking around on the Apple ][+ computers we had in grade school. I miss the days when computers could be completely understood by a single person.

Looks like there is a scan of it online: http://www.atarimania.com/documents/6502%20(65xx)%20Micropro...