PocketSphinx is a lightweight speech recognition engine, specifically tuned for handheld and mobile devices, though it works equally well on the desktop. It is released under the same permissive license as Sphinx itself.
PocketSphinx downloads have been moved to the CMU Sphinx SourceForge Site. The latest version is 0.5. To build it, you also need SphinxBase 0.4.
For more information, see The CMU Sphinx Documentation Wiki.