Halo Wars will feature a two online campaign co-operative mode and support up to six players on Xbox Live for versus multiplayer, according to US mag GamePro.
Aside from the now-standard options of co-op and multiplayer, we're also promised a shorter learning curve than traditional real-time strategy games. Don't make it too easy though or they'll be trouble on the forums, we can already sense it.
Maybe Ensemble has stripped out some of the more time-consuming resource-management parts of RTS games? For more information on Halo Wars, go read our most recent preview of the game, which alleviates some fears about transporting Halo into a RTS and putting a RTS on console.