Interestingly, the DLC will be offered in both trial and premium versions. The free trial version will include the complete Capture the Orb mode and a single-player "sample" of Deluge mode. For 560 MS Points ($7), the premium version includes the full Deluge mode as well as the aforementioned goodies.
Microsoft is also planning to release a Windows Phone 7 tie-in project later this month. Entitled Crackdown: Project Sunburst, the game offers up tower defense gameplay utilizing Bing Maps. Playing Project Sunburst will unlock new features in Deluge mode and, conversely, Deluge mode will unlock new weapons in the mobile game. The press release notes that this is the first time such integration has been seen between Xbox Live and Windows Phone 7. Assuming the platform takes off, we doubt it will be the last.
Microsoft Xbox One