This is now a repeat freebie @ Amazon UK (same link as above, and will probably drop again in the main store later) as well as
B&N (more direct link to the nook version).
Also newly free @
Kobo (not available to Canadians),
iTunes &
Google Play (both available to Canadians),
ChristianBook (ADE-DRM ePub available worldwide), and can be added to your library @
BookShout (online reading & in-app download).