I have created (or been involved in creating) various resources that I think may be useful for others. You can find them here.
• R Script Reference: A file of script that I use for my own reference while coding. Organized by type of task, and heavily commented.
• A Language Not a Letter: Learning Statistics in R: An online text for learning to code in R, written by graduate students at UIC and Alex Demos. I wrote Chapter 26 (Intro to Shiny).