The book by Dalgaard (2002) is a great resource for beginners:

http://www.springer.com/statistics/computational+statistics/book/978-0-387-79053-4

One of my R courses I have completely developed based on that book. You can download the presentations for free from here: http://dl.dropbox.com/u/7521662/Introduction_to_biostatistical_analysis_with_R.zip

Here you can find same link from the homepage and a search engine Google based.

http://www.r-project.org/search.html

In addiction you can find here the appropiate task for your analysis

http://cran.r-project.org/web/views/

I learned a lot from the videos created by the Laboratory for Interdisciplinary Statistical Analysis (http://www.lisa.stat.vt.edu/?q=past_courses)

Not free, but good, is "Discovering Statistics Using R from Andy Field, Jeremy Miles, and Zoe Field - it is great to start with R and to understand what you are actually doing.

http://www.amazon.com/Discovering-Statistics-Using-Andy-Field-ebook/dp/B00HPZ4VVM/ref=sr_1_1?ie=UTF8&qid=1389880361&sr=8-1&keywords=Andy+Field+R

The book by Dalgaard (2002) is a great resource for beginners:

http://www.springer.com/statistics/computational+statistics/book/978-0-387-79053-4

One of my R courses I have completely developed based on that book. You can download the presentations for free from here: http://dl.dropbox.com/u/7521662/Introduction_to_biostatistical_analysis_with_R.zip

For data mining this is a nice website with an associate book.

http://www.rdatamining.com/

http://www.statmethods.net/ is quite good -> Contains nice and succinct explanations with examples.

Mostly, I tend to use stackoverflow and search through the forums -> Can find some good questions and cool tricks/packages/suggestions/advice to deal with them.

Mostly I just Google looking for solutions to particular problems, but for deeper understanding, from time to time I *re-read* something more substantial. For that purpose I especially like the book by Norman Matloff, The Art of R Programming ... there is a free eBook on internet; and I also especially like the web pages (which are a book-project-in-progress) "Advanced R programming" by Hadley Wickham, http://adv-r.had.co.nz

I read some part of "R in Nutshell" by Joseph Adler. I think it is a useful book that you can download it freely :http://it-ebooks.info/book/318/ or if you Google it you can find it for download free.

There are a bunch of tutorials on YouTube,

e.g. creating histograms http://www.youtube.com/watch?v=wGW9M93YswY,

boxplots with groups http://www.youtube.com/watch?v=Yf-JGVcOMfM,

logistic regression http://www.youtube.com/watch?v=Yv05RjKpEKY etc.

just put in any engine correlation coefficient R. or open the Link http://www.r-project.org/search.html

You can try Coursera:

https://www.coursera.org/

There are some wonderful R related course.

You can learn R by doing with the swirl package. Swirl is a software package for the R statistical programming language. Its purpose is to teach users statistics and R simultaneously and interactively: http://swirlstats.com/.

Though primarily geared towards graphics, the R Graphics Cookbook is a great way to begin programming in R. This will get you started with loading packages and data, as well as plotting data in different types of charts/graphs and running basic diagnostic tests. Good luck! 

http://ase.tufts.edu/bugs/guide/assets/R%20Graphics%20Cookbook.pdf

A very easy and well constructed video series that discusses plotting in R for biologists.

http://marianattestad.com/blog

The video series by Roger Peng available in YouTube is a great way learn R.