http://www.gundogmag.com/training/
I used to hunt with a guy whose lab stayed religiously on heel all day, til we walked up a pheasant or two and dropped 'em. Then the dog ran out on command, found the dead birds and brought 'em back, just like he did when we went duck hunting. Hey, we NEVER lost a bird, and that earns a years worth of kibble IMHO.
A book I'd recommend is Gun Dog by Richard Wolters.