Data Center websites that are worth a gander:

Uptime Institute | Data Center Pulse | Data Center Journal

The 451 Group | The Whir | Green M3 | Network World

GigaOM | Loosebolts | Data Centre Solutions

Data Center Design |Microsoft Datacenters Blog

Data Center Post | Richard Jones @ Gartner

Green Data Center News |Green Monk

Next at MicrosoftPaolo Gorgo @ Seeking Alpha

Brad Hedlund