Markus Bopp of Crosstec [1] created a Mollom plugin for Joomla [2]. The plugin is code named Jollom [3] and can be customized to protect any form [4].
Welcome Joomla!
By Dries Buytaert
Source: Buytaert.net [5]
Photo Credit, Morgan Frederick [6]
Links:
[1] http://www.crosstec.de/
[2] http://joomla.org/
[3] http://www.crosstec.de/jollom-spam-protection.html
[4] http://www.crosstec.de/jollom-howto.html
[5] http://buytaert.net/mollom-for-joomla
[6] http://www.flickr.com/photos/morganfrederick94/122138564/