So a few lawyers think that profits / losses from trading bitcoins should be treated as capital gains for taxation purposes.
http://www.reddit.com/r/Bitcoin/comments/1uccfz/i_am_a_tax_attorney_here_are_my_answers_to_the/
http://www.bitcointax.info/

Is this the "consensus" opinion?

Is there open source software to figure out the long-term / short-term capital gains / losses?