argp.sh is a wrapper around getopt(1) to make life much easier for script developers (me). It's used in most of my scripts - look at them for examples of use. The essential file to install is the first one here - the script itself. Put it somewhere on your path.
Note that argp.sh deprecates process-getopt(1). There is a version of this written in 'c' in the repository.
To get the latest:
svn checkout svn://svn.code.sf.net/p/argpsh/code/trunk argpsh-code