MathWeb Search - A semantic search engine for web content based on OpenMath and MathML expressions. View Examples for a demonstration of use. - http://betasearch.mathweb.org/
Perl OpenMath to LaTeX Converter - Converts OpenMath to LaTeX. Includes a demo converter, Perl source and documentation. - http://www.maths.tcd.ie/~dwmalone/om2la.html
Wikipedia: OpenMath - Overview, history and examples of OpenMath. - http://en.wikipedia.org/wiki/OpenMath
OpenMath Critique - Open issues regarding OpenMath; a call for real-world applications to vet OpenMath. - http://www.cs.berkeley.edu/~fateman/papers/openmathcrit.pdf
OpenMath XML DTD - Document Type Definition document for OpenMath objects. - http://xml.coverpages.org/omobj-dtd.txt
RIACA OpenMath Resource - Research Institute for Applications of Computer Algebra. Includes OpenMath Java tools, JSP Taglibs and documentation. - http://www.riaca.win.tue.nl/products/openmath/