These neutral planets are exclusively PvP and earn Valor and Mercenary points to be spent on PvP gear. Many control points exist on planets to conquer.
The planet Ilum was used as an example during BioWare's little show and tell of world PvP. Fortified bases and heavy turrets will make for strategic acquisitions during these faction battles, and certain perks can be used against the enemy like bombing runs.
Mercenary points apparently buy the best PvP gear available. The beta period is expected to start for Star Wars: The Old Republic tomorrow, September 2nd.