Ultimate Auction  
   An affordable auction software that utilizes mySQL for its database.
   http://www.ultimateauction.net/

OpenScripts.com  
   Auction software written in perl and distributed under the GNU General Public License.
   http://www.openscripts.com/

Auction-Script  
   Perl/PHP Scripting. Specializing in online auction scripts.
   http://www.auction-script.com/

PHPAuction  
   E-Z Auction provides script for building auction site. All scripts come with full resell rights. [Commercial]
   http://www.e-zauctionsoftware.com/phpauction.html

BidFlux Auction Software  
   Auction software designed to be customer friendly with many similarities to eBay. Demo, pricing and product testimonials.
   http://www.bidflux.com/

Gavelware  
   Auction software written in Perl utilizing a MySQL database. Hosting and server hosting also available.
   http://gavelware.com/

RSAuction  
   A powerful membership-based auction script. Built on top of MySQL, this script provides quick, reliable performance. By RScript. [Commercial]
   http://www.rscript.com