The co-op demo for Syndicate is ready to infiltrate Xbox 360s in North America and Europe right now. The PlayStation Network will likely gain access today at the close of business on the East Coast, which is when the PSN usually updates in North America. The PSN version for Europe will have open enrollment tomorrow.
The demo covers the "Western Europe" co-op mission, as your team steals blueprints for Cayman Global (the TCBY of the future) and assassinates what may or may not be a bad guy. Hey, it's business, there's very little room for ethics.