question about plot.acf

Hi.

I'm looking for a way to plot autocorrelation, but in a little bit
different way than
plot.acf does. Instead of plotting NxN graphs (assuming N is ht enumber of 
variables) like plot.acf does, I'd like to have one graph of sum of
all autocorrelations
vs. lag. Is there any function that already does this or should a try
to write it
myslef ? 

Thanks a lot.