Books:
Freely Downloadable:
See the ''Manuals'' link in http://www.r-project.org/
Others:
Tutorials:
- Introduction to the langage and basics statisticals tests: http://www.cyclismo.org/tutorial/R/
- R for programmers: http://heather.cs.ucdavis.edu/~matloff/R/RProg.pdf
Documentation:
- All R manuals are on the CRAN website: http://www.cran.r-project.org/
Special Links:
- A lot of example of graph, with code: http://addictedtor.free.fr/graphiques/