Internet links to South Dakota government agencies statutes, regulations, cases, etc. are posted by FindLaw and Washlaw Web. Primary legal materials are also available from Lexis, Westlaw and LOIS. Google Scholar has free cases back to 1950; subscription sites Versuslaw and Fastcase also have cases back to 1950.
To check on the status of a pending bill, call the Legislative Research Counsel at 605-773-3251.
The South Dakota Legal Research Guide (W.S. Hein & Co.) discusses South Dakota legal resourses, but check to see if the edition is current enough for your purposes.
For questions about South Dakota legal materials, copies and/or inter-library loan, try calling the University of South Dakota's
Law Library (605-677-5259).