Frank,
Pads and the other packages are  great but a bit pricey if you are just playing around or learning for information purposes only. There is a free cad download at http://www.cadstarworld.com/downloads.asp called Cadstar. Some what limited, 20 components 100 pins, but you get what you pay for.   Lavenir has a free Gerber viewer  http://www.lavenir.com/Download/download.html and a cheap Gerber editor, ViewMaster (about $300 or $400 ). Graphicode http://www.graphicode.com/index.cfm?section=download also has a free viewer. Both of the viewers will let you edit but not save. I use the Lavenir editor daily I like it pretty well but I'm not a pcb designer I just do step and repeats and add tooling holes and feducials. I also do product design reviews and have spotted a lot of potential problems using a Gerber viewer that didn't show up in the pcb layout software we use.
Hope you find this info useful,
Dan