I came across this useful posting by Gregor Gorjanc in the r-help ML.

• R graphical manuals (this is awesome page as there are all help pages of all packages on CRAN and probably even more and all graphics examples are displayed! - more than 8000 images!)

bg9.imslab.co.jp/Rhelp/

This is a very nice addition to already existing R graph and movies galleries

• R Graph Gallery

addictedtor.free.fr/graphiques/

• R Movies Gallery

addictedtor.free.fr/movies/