I'm able to make things work out fairly well, but I'd like to get a better basic understanding of ISO and Aperture settings.  Anybody have a great simple tutorial resource?

Here you go! http://www.luminous-landscape.com/tutorials/understanding-series/understandexposure.shtml

If you've got some time on your hands and enjoy reading, one of the better investments I made as a photographer was to pick up a copy of Ansel Adams's Technical Series.  "The Camera", "The Negative", and "The Print" are well worth the read.  Some of the material may seem a little dated (who's printing on Seagull paper?) but in fact most of it translates quite well into digital photography.  I'm re-reading "The Camera" right now, and it's an outstanding refresher.

Tom