I was having a little trouble getting RStudio to process BibTex entries and compile a LaTeX file. Bumping around on the great RStudio help forum, I found this entry, which pointed me in the direction. I needed to set a system environment variable in R to let RStudio and R know where to look for the proper BibTex style, LaTeX input, and BIB input files. I have put up a little Gist on GitHub that shows how I got it done, since I had never messed with R Environment variables before.