The translator Steven Lattimore is still alive. GP probably won't live to see the translation become public domain. As an alternative: read the J. M. Dent translation and then, if you want to study it from first principles, learn Ancient Greek for the real thing.[1]
That's right, Lattimore is not public domain. It's ok though, our focus is on the original work, and if it's in another language we just pick the best one that suits our needs. Other people in the club have stuck to Crowley though, and I'm going to check out Dent (per the sibling comment) when I have time.
[1] http://www.perseus.tufts.edu/hopper/text?doc=urn:cts:greekLi...