Indie in the Halo Wars forum pointed out some listings from the jobs page at Ensemble Studios. What he found particularly interesting were two items for MMO environmental and concept artists; what I find interesting are the console programmer and Xbox Live developer positions.

Ensemble hasn't really said a word yet about the features of Halo Wars, but it seems logical to conclude they'd at least be trying for multiplayer on Xbox Live. If not... what's the point, really?