International Society for Bayesian Analysis: Promotes the development and application of Bayesian statistical theory and methods useful in the solution of theoretical and applied problems in science, industry and government.
Bayesian Abstract Archive: An archive of abstracts of research papers on Bayesian statistics. Sponsored by ISBA and SBSS.
Bayesian Blind Source Separation: An online paper on solving the cocktail party with Bayesian statistics. Includes general introduction to the problem and links to related works.
Measurement Decision Theory: Includes rules, examples, and information about adaptive testing and sequential decisions. Main ideas are presented using a binary classification (pass/fail) test and a sample three-item test.
Probability Theory As Extended Logic: A monumental online book by the late E. T. Jaynes on Bayesian inference. Also has a number of related articles by other authors.
The Bayesian Songbook: A collection of often humorous songs with bayes-related lyrics sang to popular tunes on the last nights of the Valencia meetings on Bayesian statistics. Lyrics in LaTeX and postscript formats. Wav files of some songs available.