Author Joseph Adler has written an excellent book for those of you starting your exploration into R.  It's subtitled "A Desktop Quick Reference", but it can be read from cover-to-cover due to the author's witty style and attention to detail.  Not only does this book discuss the basics of R, but it also has several chapters on graphics in R as well as statistics.  I highly recommend this book.  To order this book from Amazon, click on this link: R in a Nutshell: A Desktop Quick Reference.