John Bear's R checklist

Cheat Sheet: Tom Short's Cheat Sheet

The Best Online R Textbooks  Statistics Textbooks Online

Introduction to the R Project for Statistical Computing for use at ITC  by Rossiter (3.0 MB)  (PDF)
The R Guide by Owen (467 KB)  (PDF) Introduction to Probability and Statistics Using R by Kerns    (PDF)
simpleR – Using R for Introductory Statistics by Verzani   (PDF) Practical Regression and Anova Using R by Faraway   with R examples    (PDF)
An Introduction to R by R's Core Development Team (HTML) Introduction to Statistical Thought by Lavine (43MB)   with R examples   (PDF.gz)
icebreakeR by Robinson (3.6 MB) (PDF)
Introduction to Probability by Grinstead and Snell   with Matlab examples   (PDF)
An Introduction to R: Software for Statistical Modelling & Computing
by Kuhnert and Venables   (4.5 MB zip file)

R Graphics Textbooks Put a call to browser() in the function of interest.
R Graphics by Paul Murrell   (HTML) After an error message try traceback()
Using R for Data Analysis and Graphics
Introduction, Code and Commentary by Maindonald
Try binary search

Web Search R help functions
RSiteSearch by Jonathan Baron
apropos('regexp') # Search for loaded symbols (functions, etc.)  by Sasha Goodman help(functionname) # Tells how to use the function'regexp', agrep=F) # Search the help system database fields
For Hard Questions'pattern') # Search help db using Levenshtein edit distance
Official R Manuals library() # Shows loaded packages
Frequently Asked Questions library(packagename) # Loads the package
CRAN Task Views vignette('packagename') # Overview of package
Other Contributed R Documentation ls(package:packagename) # Functions in package

ls() # Shows currently defined local functions & variables

search() # shows things on the search path

args(functionname) # Shows the names of the function's arguments