[R] automatic SI prefixes as ticklabels on axis

[Jonas Stein]

i want to plot values with frequency on a logarithmic x axis.
similar to this example that i found in the web:
http://www.usspeaker.com/jensen%20p15n-graph.gif

I would like to convert long numbers to si prefix notation 
like in the example

(200000 to 200k, 35000000 to 3.5 M)

Of course i could create labels by hand, but
i have many files so i need some automatic function.

Has anyone done that in R?

Kind regards and thank you for your help,

-- 
Jonas Stein <news at jonasstein.de>