Neal, R. M. (2001) ``Defining priors for distributions using Dirichlet diffusion trees'', Technical Report No. 0104, Dept. of Statistics, University of Toronto, 25 pages: abstract, postscript, pdf.The functions are written in R, version 1.1.1. Except for the examples of divergence functions, they will probably work in S-Plus too, but I don't recommend trying it, for performance reasons.
First (and probably only) release of 12 March 2001: tar archive.