I second the 100% cotton dress shirts and undershirts. The undershirts really do make a difference. And make sure to wear the crew-neck or V-neck and not those awful A-neck "wife-beater" shirts. Not only do they look bad when they show through your shirt, but they don't protect the armpits of your shirt from sweat.
Wear light colors and light-weight suits. Unlined or partially lined suits should be cooler.
I've got the material for a tan linen suit, so I'm going to give that a try this summer as well. I don't suppose seersucker is really worn in Kansas (I've not seen it there), but I could be wrong.
Make sure your shirt collars are well-fitted, as that makes for better ventilation.
Getting used to a suit in hot weather is also important. I think a lot of people just give up after one or two hot days, but I've found that you can get used to it if you wear suits as the weather is getting hotter and stick to it.
BTW, Bulldog, in what part of Kansas do you live? I'm in Kazakstan, but my parents are in Kansas north of Wichita, so I do a lot of my shopping there. Just wondered if you've found any good stores there? It would be great to have an AAAC gathering in Kansas sometime.
Steve