I don't know if anyone has seen this yet, but planetGenesishttp://planetgenesis.sourceforge.net is a great tool for creating noise textures. It can create planar textures as well as textures that map to the surface of a sphere without pinching. It can be used to create a variety of combinations of Perlin, Worley, Fault and now Simplex noises(the last only if you compile from the latest cvs source. It is in java and so should be very portable.
PlanetGenesis produces 16-bit png's(excellent for povray or bryce terrains) as well as a number of 3d object types(including, I believe, .obj). In combination with gradient mapping in gimp or photoshop, it can produce excellent surface textures.
The original author is David Burnett with some work by Sid Datta. I'm a little proud of it because I recently made some humble additions to the program(most significantly that simplex noise ).
It's also a good introduction to a simple node tree texture model. I often experiment with it before trying terragen2, which takes a long time to render and is unbelievably complicated.
Have a look, folks.