R vs. Python breakdown, from Learn Analytics blog's "Clash of the Titans" http://bit.ly/1IQp4jy
Learn Python the Hard Way, 3rd ed., by Zed A. Shaw
The Little SAS Book: A Primer
Statistical Programming Languages Infographic
R Cheat Sheet for data mining, data exploration, data science in R
Cheat Sheet: machine learning algorithms, data science both for R and Python
CodeSchool's free clas on learning R.