The website, http://www.nltk.org, says mid 2011 in a very vague manner. I would like to start using NLTK however I have done a fair amount of work with Python 3.x and I don
Here's the alpha release: https://github.com/nltk/nltk3-alpha
Alternative NLP: TextBlob is fully Python 3. https://github.com/sloria/TextBlob
Tutorial: http://www.stevenloria.com/how-to-build-a-text-classification-system-with-python-and-textblob/