First thing I would do is go to your local library and see if they any books on the history of your area, especially the prehistory before white settlers moved in. You can usually get some pretty good info that way.
Next I would ask around and see if anyone collects artifacts and see if there are any local chapters of collectors who meet and discuss their finds and collections and see if you can become a member.
You can also just take a drive out thru some farmland and stop and talk to some farmers and see if artifacts are found on their property and if you can get
permission to look around. That point I can't stress enough.
ALWAYS GET PERMISSION FIRST BEFORE ENTERING SOMEONES PROPERTY!! I have found quite a few new sites by doing this. Another thing that helps in this endeavor is to have some young kids with you. Most farmers are more apt to let you on their property if they see you have kids with you and are trying to educate them on Indian artifacts. I know it might seem kind of dubious, but hey it works.
Lastly, you can buy yourself some books on artifacts from your general area. I will give you a link to a site that has all kinds of books on artifacts and I'm sure you can find something that focuses on your area. Good luck.
http://www.hothemhouse.com/
Surely there should be some native american artifacts in my part of the world... 
