A great mailorder source for beneficial insects (with an informative website) is Buglogical Control Systems.
For organic alternatives to chemical pesticides, check out Gardens Alive!
A good source for greenhouse supplies is Charley's Greenhouse. (We like their Propagator's Label.)
Our greenhouse was a modular kit from Santa Barbara Greenhouses.
For SunGro's Sunshine mixes and perlite in bulk, try American Horticultural Supply with locations in Camarillo, Modesto, and Vista.
Another good source of bulk nursery supplies (pots, flats, fertilizer) is McConkey Co.
For organic gardening, what could be better than a handmade Woven Garden organic raised planting box.
The Helpful Gardener was recommended as a friendly place to ask questions; look for the NATIVE SPECIES section for help with gardening with native plants and for wildlife.