Video courtesy of IGN.
It looks like Double Fine hasn't given us a release date on their Iron Brigade DLC. But we'd like to think from this video that it's on it's way, and not too far from now, either.
SPOILER ALERT: From Double Fine's initial statement on the DLC, "Rise of the Martian Bear," Vlad was defeated, but managed to transfer his consciousness into his pet bear. Said bear then hot-footed it to Mars to rebuild the forces, and is now coming back to finish what Vlad has started. Sounds good to us. Any excuse to keep playing Iron Brigade is a good one.