Project local libraries (reproducible research)

Hi all,

I was wondering if any one had scripts that they could share for
capturing the current version of R packages used for a project. I'm
interested in creating a project local library so that you're safe if
someone (e.g. the ggplot2 author) updates a package you're relying on
and breaks your code.   I could fairly easily hack together, but I was
wondering if any one had any neat scripts they'd care to share.

Hadley

Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/