Detailed instructions for using this script are given in my Instructable for it.
For a small, paper sundial project, go here.
You must enter the width of the sundial you wish to build, enter either a zip code or latitude/longitude, and select your timezone and daylight savings option. Required options are in bold.
The source code for this perl script is available here. You need to get sundial.pl and zipcodes.dat, and keep them in the same directory. You will also need the PDF::Create perl package.
I used formulae from here and here.
The script (not including PDF::Create) is copyright (c) 2011 Alexander R. Pruss, and is available under a two-clause BSD license.. Alexander R. Pruss hereby releases into the public domain any and all copyrightable visual elements in the output. Courtesy suggests, though the law may not require, that credit be given for use of the script when you use its output.