If you want syntax highlighting when viewing docs and source at search.cpan.org, you don't actually need to use Greasemonkey. You can do it with Plack and be up and running in just a few minutes.
Last night I gave a lightning talk about this at Toronto.pm and I've just posted the slides
Basically, all you need to do is this:
git clone http://github.com/ioncache/Plack-Middleware-HTMLify.git
git clone http://github.com/oalders/cpan-mangler.git…