NLTK

• NLTK official website: http://www.nltk.org/
  • Download and install three packages: Python (2.6 recommended), PyYAML, and NLTK.
• NLTK data (all): download (also downloadable using the NLTK downloader - nltk.download())

Others

• Python Tutorial: http://docs.python.org/tutorial/
• OpenNLP: http://incubator.apache.org/opennlp/
• WordNet: http://wordnet.princeton.edu/