Details for how to vote for your preferred story ending to Time's Arrow: Black Swan are now up on Abaddon Books' Facebook page.
Basically it's like this. Once you've read the second eBook in the eBook trilogy that will ultimately become Pax Britannia: Time's Arrow, head over to the Abaddon Facebook page and post 'A' or 'B' after the status update that starts 'WHAT WILL COME OF OUR DASHING HERO NEXT?'
Or, alternatively, you can email your choice of 'A' or 'B' to firstname.lastname@example.org.
You have until 25 June 2012 to cast your vote.