Feel free to add any you think are helpful, or review any you have tried!
The R Journal is the refereed journal of the R project for statistical computing. It features short to medium length articles covering topics that might be of interest to users or developers of R, including Add-on packages: short introductions to or reviews of R extension packages. Programmer's Niche: hints for programming in R (or S). Hints for newcomers: Explaining aspects of R that might not be so obvious from reading the manuals and FAQs. Applications: Examples of analyzing data with R.
I subscribe to the RSS feed of this blog, it often offers useful tips, applications and resources–JCU
Brian Knaus' recommendation for a intro to R book (Thanks to Heather Lintz!):
How to connect to: