Corpora: freely available PCFG parsers

[John Colby]

As a component of a grammar inference system, I require a
probabilistic CFG parser that is fairly efficient and computes
inside/outside probabilities.  An implementation of the inside/outside
algorithm is also need.  Does anyone know of freely available software
written in C or C++ which meets these requirements?

-John Colby
 University of California, at Santa Cruz