[BioC] plotDensity in a multiple-figure enviroment

[zhihua li]

Hi all.
I have a microarry gene expression data in the form of a matrix, where rows 
represent genes and columns represent conditions. plotDensity in "affy" 
package can draw a density distribution curve for each column and put them 
in a single plot. I wanna draw a density distribution curve for each 
colomn, put them each in a seperate plot, and put all these plots in a 
single page.  What should I do?
Thanks to all!