Do a google search, with criteria = companion planting edu. There's a few nice articles, such as http://www.aces.edu/counties/Limestone/MastGard/companions.htm:
Plants with strong odors do confuse, deter, and oftentimes stop certain pests.
-Certain plants hide other certain plants we don't want detected.
-Certain plants, and especially herbs, are considered nursery plants for the good insects providing shelter, nectar, pollen, and even dark, cool moist spots for lacewings, lady beetles, parasitic flies, and wasps.
-Certain plants serve as a 'trap' crop, which pushes insects away from other essential plants (rue's bad odor and disagreeable taste will keep even the most persistent of pests away).
-Certain plants create habitats which attract more beneficial insects (such as lady beetles, praying mantis, and ambush bugs).
There's also a rather critical one, http://www.puyallup.wsu.edu/~linda%20chalker-scott/horticultural%20myths_files/Myths/Companion%20plants.pdf
Years ago I picked up a used copy of Rodale's The Encyclopedia of Organic Gardening, and it in part describes companion planting similarly to a guild- certain plants will benefit from the shade of other plants; some plants bloom early before their neighbors have a chance to leaf out and shade them.
I have a feeling that the reaspon there's not much scientific data on this is because of funding sources. Who is going to fund a study that will prove a way to minimize chemical intervention? Not the chemical companies.
Start small, with the simple concepts, or you'll get overwhelmed. Then branch out as you feel comfortable.
Good luck (and welcome!).