Conditional plot labels

x <- seq(0, 10, length=100)
y1 <- sin(x)
y2 <- cos(x)
y3 <- x^2/100
y4 <- 1/x

d <- data.frame(x, y1, y2, y3, y4)

library(reshape)
dm <- melt(d, id="x")

dm$type1 <- rep(LETTERS[1:2], each=2*length(x)) # dummy factors
dm$type2 <- rep(letters[1:2], each=length(x))

library(ggplot2)
p1 <-
qplot(x, value, data=dm, geom="line", facets=type1~type2)

p1 # you can customise the appearance if the default doesn't please  
you

library(lattice)

p2 <-
xyplot(value~x|type1*type2, data=dm, t="l") # here the strips are on  
top of each other by default

library(latticeExtra)

useOuterStrips(p2) # this makes the layout more like you want

Hi all,
I'm trying to do multiple graphs in a window like this:

       ___  ___   ___
ylab  |__|  |__|   |__|
       ___  ___   ___
ylab  |__|  |__|   |__|
       ___  ___   ___
ylab  |__|  |__|   |__|
        xl     xl     xl

If I try to put the labels manually, some graphs become smaller than
other and the output is really ugly.
In the thread title I put the word "conditional" because I'm trying to
do a function, and in that function I want to print ylabels if the
plot positions is at first column of the graph matrix, and xlab if the
position is at last row of matrix.

How can i achive this two things?

Thanks for your help

-- 
CdeB