One of the best books of maps for Oklahoma is John Wesley Morris, Charles R. Goins, and Edwin C. McReynolds, Historical Atlas of Oklahoma, 3rd ed. Norman, Oklahoma: University of Oklahoma Press, 1986. ( Family History Library film 1,000,357 item 3.)
The Family History Library has several maps, including some of the Indian Territory.
Printable maps are also available from the National Atlas of the United States -- http://nationalatlas.gov/printable.html