You have already had one response that
interpreted "learn R" as use R to do
statistics. I have a rather different
interpretation of "learn R". An answer
to that interpretation (learn the
mechanics of the language) is:
If you haven't already look at Introduction to R, please follow this link "http://cran.r-project.org/doc/manuals/R-intro.pdf". There are several books which will teach you R, please look at online retailers like Amazon, Ebay etc.,
Online search for specific task will also to help you to gather knowledge, what I mean is, search online for "summarize a data table in R" it will produce a lot of results and you will find different people saying different ways to get the task done which will help to learn more R coding. Hope this helps.