From BEAST Software
BEAST is a cross-platform program for Bayesian MCMC analysis of molecular sequences. It is entirely orientated towards rooted, time-measured phylogenies inferred using strict or relaxed molecular clock models. It is not intended solely as a method of reconstructing phylogenies but also as a framework for testing evolutionary hypotheses without conditioning on a single tree topology. BEAST uses MCMC to average over tree space, so that each tree is weighted proportional to its posterior probability. We include a simple to use user-interface program for setting up standard analyses and a suit of programs for analysing the results.
The complete source code for BEAST is now distributed under the GNU Lesser General Public License and the source code, bug tracking database and information for developers is now hosted by Google: