I see a lot of people have mentioned the Indiana DNR, but there are several other states that will ship out of state for quite reasonable prices. I'm hoping to buy from Kentucky ( State Nurseries and Tree Seedlings | State Nurseries and Tree Seedlings ) or Missouri ( About Missouri's State Forest Nursery | Missouri Department of Conservation) next year. If you do order from out of state, it might be wise to ask a forester or Ag extension agent to confirm you're not getting an invasive, unless you're willing to manage it. Another fantastic resource (IMHO) is tcpermaculture.com. It's a blog by a Dr. who does fabulous write ups on different plants, including trees. It's also got some great introductory explanations of Permaculture techniques in easy to read format. It would be the first site I suggest to someone interested in learning what permaculture is. Just go to the article index.