Bob Warfield, the creator of G-Wizard, has put together this incredible reference:
G-Wizard Calculator Feeds and Speeds Examples for CNC Beginners:
http://www.cnccookbook.com/GWCalcBeginnerFeedsSpeedsExamples.htm
Highly recommended! I have been using G-Wizard for a while now, and I learned something from this article. Wish I’d had it when I first started!