What to read, Where to look?

As a child the older members of the family often told me that one of my great grandmothers was Cherokee. Most of the older members of the family are gone now. Is there any way to investigate this? I know almost nothing about researching geneology or if it would help if I did. Also I have always had great respect for native american culture even though I'm mostly ignorant of it. I suspect many non-native americans are in the same boat as I am. Can anyone recommend any books, websites etc with either general or specific info? I have read Bury My Heart at Wounded Knee which I highly recommend to anyone who hasn't read it. Also, I live in southeast missouri. Is there any info on native americans specific to this area? Thanks for any help you can offer.