globally changing typewriter font scale

[Guy Hindell]

Hi all - I'm sure there's a TeX trick to doing this, I just don't know 
what it is, so...

Is there some way I can scale the size of fixed pitch fonts (courier)? 
In my preamble I have \usepackage[scaled=0.92]{helvet} which tweaks the 
size of the sans serif fonts down to something which better matches the 
serif font (times), but can't find an option to do the same to the fixed 
pitch fonts. I find I frequently have to put blocks of material which 
use fixed pitch into \footnotesize ... \normalsize blocks to avoid 
overfull \hbox warnings from pdflatex.

Many thanks

guy