Software for NLP
http://www-a2k.is.tokushima-u.ac.jp/member/kita/NLP/nlp_tools.html

Apple Pie Parser
http://nlp.cs.nyu.edu/app/

The Stanford Natural Processing Group
http://nlp.stanford.edu/downloads/lex-parser.shtml

AGF Grammar Work Lab
http://www.agfl.cs.ru.nl/

INTEX Linguistic Development Environment
http://www.nyu.edu/pages/linguistics/intex/

Nooj
http://perso.orange.fr/rosavram/pages/noojpag.html

Natural Language Tookkit
http://nltk.sourceforge.net/

OpenNLP
http://opennlp.sourceforge.net/