Just read about this on Falstaff's blog. Scary stuff.
(Why is that I didn't read about this even once in the newspapers or saw any coverage of this story on TV when I was in India in December? Don't answer that - I know.)
Via Falstaff (link to Freebinayaksen.org), Via Space bar (link to kafila.org)
Aid India's online petition
Another website (presumably based in UK) that is also seeking the release of Dr. Sen.
Tehelka has a "list of charges and evidence against Dr. Binayak Sen"