Automatically resize A4 printouts to letter?

[Reid Priedhorsky <reid@reidster.net>]

Dear all,

Every so often I run into a document I would like to print, that is sized
for A4 paper. When I try to print it, my printer (HP LaserJet 4m) demands
A4 paper, which I don't have and which really stops things up when I have
a pipeline of documents being printed.

Is there a configuration or a recipe to cause these A4 postscript files to
be automagically rescaled to letter-size during the spooling process?

Thanks,

Reid