Details about the individual programs that make up the BEAST package can be found here.
What does BEAST do?
 This is a list of some of the models and features in BEAST:

Timescaled phylogenies  While BEAST focuses on estimating rooted and timemeasured phylogenies, it can analyse both contemporaneous (isochronous) and noncontemporaneous (heterochronous) sequences.

Tipdated analyses  For noncontemporaneous sequences, when the differences in the dates associated with the sequences comprise a significant proportion of the age of the entire tree, these dates can be incorporated into the model providing a source of information about the rate of substitution.

Relaxed molecular clocks  Constant (strict), variable rate (relaxed) and local (allowing different clades in the tree to have different rates) molecular clock models.

Wide range of substitution models  Available substitution models include JC, HKY, TN93 and GTR for nucleotides, Blosum62, CPREV, JTT, MTREV, WAG, LG and Dayhoff for amino acids and the models of Goldman and Yang (1994) and Muse and Gaut (1994) for codons.

Substitution model heterogeneity across sites  Different substitution models can be specified for different sets of sites. For example, each codon position can be allowed a different substitution matrix and gamma model of rate heterogeneity.

Flexible model specification  The modelspecification file format allows considerable flexibility. For example, it is possible to specify that each codon position has a different rate, a different degree of rate heterogeneity but the same transition/transversion ratio.

Flexible choice of priors on parameters  Any estimable parameter can be given a prior probability distribution from a wide range of options. Priors can also be used to introduce information — i.e., a known distribution for a substitution rate.

Coalescent models of population size and growth  Various parametric models of coalescent population growth can be used including constant population size, expansion growth, exponential growth, and logistic growth. Additionally, multiepoch parametric coalescent models are also available: constantlogistic, constantexponentialconstant, exponentialconstant, etc.
A range of implementations of multichangepoint, nonparametric coalescent models are available such as the Bayesian skyline, skyride, and skygrid (the latter, with or without covariates).
These models basically act as priors on the ages of nodes in the tree but their parameters can be sampled and estimated.

Multilocus coalescent models  Two or more unlinked genes can be given the same coalescent population model but a different substitution process and tree, allowing the production of multilocus coalescent inference.

Phylogeographic models  .

Discrete and continuous traits and the comparative method  .

Hierarchical models  .

Bayesian model selection and testing  .
Acknowledgements
Developers
 BEAST was designed and developed by Alexei J. Drummond, Andrew Rambaut and Marc A. Suchard:
 Alexei J. Drummond  Department of Computer Science  University of Auckland
http://compevol.auckland.ac.nz
alexei–at–cs.auckland.ac.nz 
Andrew Rambaut  Institute of Evolutionary Biology  University of Edinburgh
http://tree.bio.ed.ac.uk
a.rambaut–at–ed.ac.uk 
Marc A. Suchard  David Geffen School of Medicine  University of California, Los Angeles
http://faculty.biomath.ucla.edu/msuchard/ (Warning: 1990’s style)
msuchard–at–ucla.edu  BEAST and modules within it have developed by

Alex Alekseyenko, Daniel Ayres, Guy Baele, Trevor Bedford, Filip Bielejec, Erik Bloomquist, Aaron Darling, Matthew Hall, Joseph Heled, Sebastian Hoehna, Philippe Lemey, Wai Lok Sibon Li, Sidney Markowitz, Vladimir Minin, Michael Defoin Platel, Walter Xie
 As an Open Source project, BEAST has benefited from contributions and assistance from a large number of people over the years. In particular we would like to thank:

Peter Beerli, Gytis Dudas, Roald Forsberg, Jess Hedge, Simon Ho, Mark Holder, Denise Kuehnert, Paul Lewis, Gerton Lunter, Sam Lycett, Oliver Pybus, Tulio de Oliveira, Jayna Ragwani, Beth Shapiro, Korbinian Strimmer, David Swofford, Ziheng Yang
Funding
BEAST has been supported at various times by:
Project grant 092807