Machine Learning for Hackers gets you started using R for machine learning. The book does a good job telling you how to install R and where to find help.
All the code and data for this book is on https://github.com/johnmyleswhite/ML_for_Hackers.git
Sadly there is not an R package.
There are lots examples on how to explore data using ggplot2. Other package covered include plyr which they equal to map reduce. tm package which is used in polynomial regression. glmnet and the Lamda function. K-Nearist neighbor algorithm which uses the class package.
Also good information on how to work with api’s and json using RCurl. RJSONIO and igraph.
This book is written for hackers, people who already know how to code. The theory is found in other books. More detail on specific techniques and R code is in other books. This book is a good starting point for machine learning and R.