Formerly PCCTS, a language tool which provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing C, C++, or Java actions. [Public Domain]

Free grammars available for ANTLR, including Java 2 grammar and tree generator/parser, HTML grammar and IDL grammar.

The author discusses the experience of using ANTLR, with an introduction to the tool. (Gary L. Schaps / Dr. Dobb's Journal)

Visual Parser Debugger for ANTLR 2.x. [Public Domain]