Didrik Vanhoenacker has put together a site called Ecological Statistics with R.
The site provides several resources useful to researchers who are new to R. It gives advice on installing R. It discusses how to use several standard techniques (ANOVA, regression, 2x2 tables, logistic regression, and non-parametric tests). It also covers the use of R Commander (i.e., R with training wheels), which is particularly useful for researchers who are transitioning from menu-driven statistics programs such as SPSS.
