http://neotextureedit.sourceforge.net/

NeoTextureEdit is an easy to use graph-based procedural seamless texture editor. Using continuous basis functions it can generate arbitrary resolution images without quality degradation. Its main purpose is to produce high quality textures for real time rendering applications that can be stored in a few kB and synthesized on application startup. But it can also be used to generate off-line images.

The most current version as well as the sourcecode can be found at the sourceforge project page: http://sourceforge.net/projects/neotextureedit/