Bosnian, Croatian, Serbian Project, by Dr. Curtis Ford of University of South Carolina-Columbus: "The first interactive tutorial on reading and pronouncing Bosnian, Croatian, and Serbian." Course is downloadable.
Intensive Elementary Bosnian/Croatian/Serbian, course syllabus by Professor Danko Sipka, Arizona State University, Critical Languages Institute, provides excellent materials and links as well as online exercises and drills. Note: You need to scroll down to reach these materials. You can also take this course online for credit.