A great book for R graphics is here. Its especially useful for people who are new into R and or using graphical function primarily.
http://www.stat.auckland.ac.nz/~paul/RGraphics/chapter2.html
This is a good textbook till the new edition November 2008 release of Bob Munchien’s R for SAS and SPSS Users (http://www.springer.com/statistics/computational/book/978-0-387-09417-5 )
The existing free copy is at http://oit.utk.edu/scc/RforSAS&SPSSusers.pdf