http://www.rockybid.com
http://www.quibids.com
http://www.swoopo.com
http://www.skoreit.com
http://www.swipebids.com
http://www.beezid.com
http://www.for10cents.com
http://www.bidcactus.com
http://www.pennyauctionwatch.com/
http://www.pennyauctionscript.com/ – $1000 base
http://www.moneymakersnetwork.info/products/Swoopo-Clone-PHP-Script.html – $19
http://www.ajaxphppennyauction.com/ – Script for $99