The Postal Address Geo-Coder (or PAGC) is a command line program written in ANSI C that uses an address-ranged street network shapefile and an address list (in a dbf format file) to create a point shapefile that provides the longitude/latitude coordinates of each matched address, and maintains the attribute information in the original address database file. PAGC is Open Source, and is released under the GNU Lesser General Public License. PAGC has been built and tested under GNU-Linux, Microsoft Windows, and Mac OS X. However, since it is written in ANSI C, it should be posible to build and use PAGC under any operating system that provides a command line interface.
While PAGC is currently a command line program, we have a major initiative to create a C library based on the code and algorithms used in the command line program. This should allow other open source GIS oriented projects to add postal address geo-coding features to their software.