Twitter corpus for Sentiment Analysis from a class (cs224n)at Stanford.
Class page:
https://sites.google.com/site/twittersentimenthelp/for-researchers#Where_is_the_Tweet_corpus_8553
http://www.stanford.edu/~alecmgo/cs224n
Y. Chen, G. Dong, J. Han, B. Wah, and J. Wang. Proceedings of the 28th international conference on Very Large Data Bases, page 323--334. VLDB Endowment, (2002)