Duncan Temple Lang's article "In Search of C/C++ & Fortran Routines" in R News Vol 1/3, September 2001 is definitely worth reading (even though it's mainly about calling C from R): http://cran.r-project.org/doc/Rnews/Rnews_2001-3.pdf and you should have a look at "Writing R Extensions" : http://cran.r-project.org/doc/manuals/R-exts.pdf James