The Probability and Statistics Object Library is an NSF-supported virtual library of web-based "objects" for teachers and students of probability and statistics. The "objects" are either standalone applets or components that can be used to build other applets and embedded into other components. The components are written in Java and are organized into "packages" according to their type. All objects (including the source code) are freely available for use, modification, and re-distribution under the terms of the General Public License. The Probability and Statistics Object Library can be accessed at http://www.math.uah.edu/psol.