Undead Labs have confirmed that successful XBLA release State of Decay will see release on PC before the end of the year. The exact timing is unknown, but Undead Labs hope to have it out as soon as possible.
The PC version will offer improved graphics and framerate, but sadly no mod tools.
"What the PC version also won't have are modding tools (for time/testing reasons), but we have no objection to mods or modders, and we look forward to seeing what our PC players come up with."