(If you order it using the above link, we get a small kickback. Thanks!)
Mapping Hacks
by Schuyler Erle, Rich Gibson, and Jo Walsh
Mapping Hacks Code Page
This is an archive of some of the code from Mapping Hacks. Also take a look at The Google Maps Hacks page.
track2shp.zip contains track2shp.pl, to convert a track log in a text file to a shapefile, and trackgpx2shp.pl to convert a track log in a GPX file to a shapefile.