warning... free BUT NOT open source !

Richard Rosemann released some new cool filter here the list of its free filters
http://www.richardrosenman.com/software/downloads/

A new version of PixelBender...the plugin version http://labs.adobe.com/technologies/pixelbenderplugin/ require Adobe (PhotoShop and/or AfterEffect and/or Flash) BUT there is a free standalone version
http://www.adobe.com/devnet/pixelbender.html that may be used not only to run but also to create new filters ( that anyway will require or the stand alone or the plugin to be used

Very last the most complete list of free PS filter is on http://www.thepluginsite.com/resources/freeps.htm
(BTW this news come from the last pluginside newsletter )

Thanks PC.