I recommend installing RStudio as GUI. It considerably facilitates working with R (syntax highlightning, bracket-matching, error-checking, hints on functions, symbols, and arguments whily typing, etc etc., and some house-keeping functions like installing add-on packages and so on can be done in a menu-driven way).
There are many web sites which teach/give tutorials/documents about R like www.datacamp.com and others. You need to learn basic data types and syntax at first. If you need to go further, you can learn basic programming skills like loops and functions. If your focus will be about fundamental statistical methods, I can recommend you the book by Kabacoff, R in Action.
I recommend installing RStudio as GUI. It considerably facilitates working with R (syntax highlightning, bracket-matching, error-checking, hints on functions, symbols, and arguments whily typing, etc etc., and some house-keeping functions like installing add-on packages and so on can be done in a menu-driven way).
Jochen is right. RStudio is the single most powerful ally you have in getting to grips with R. Prior to that, I would find that I had spent half a day persuading R to do something that I could have done in Stata while having a conversation on the phone.
Another opportunity is to use "swirl". It's an interactive R-based package to learn basics in R programming. You can install various courses that address different aspects that you might be interested in:
In addition, Rcmdr gives graphical interface. I recommend it for people who doesn't feel easy with command instruction. However it is not supported by all packages.