QuickR
There is a new (I think) website for learning R that looks pretty decent: Quick-R(http://www.statmethods.net/). It was created by Robert Kabacoff, whom I had the pleasure to meet several months ago. We discussed R briefly at that time and he was just getting into it. Apparently he has been busy! The intended audience are users of SAS/SPSS/STATA transitioning to R. If that fits your bill, go ahead and take a look. If it doesn’t and you are already an experienced users, I am sure there are more than a couple of people you can point the website to.