Maybe you haven't finished BioShock yet and you need to install it on another machine. Or invasive online DRM systems give you the creeps. Whatever the reason, PC owners of 2K Australia/2K Boston's FPS can now "deactivate" their installed copies and move them to another box, without having to worry about getting a nasty message telling them they've used up all their activations.
Just hit up the Cult of Rapture website to download the utility that makes the magic possible. Full instructions on how to use the tool are also available.
BioShock Activation Revoke Tool Available Now [The Cult of Rapture]