SoE's promise that PlanetSide 2 will be on Steam has been made good.
As the developer promised a few months ago with the launch of the game's beta, PlanetSide 2 would be coming to Steam.
It looks like the developer's promise has been made good, as PlanetSide 2's Steam page has gone live. Unfortunately, the game will be locked out until its release, so it looks like preloading the game won't be an option.
PlanetSide 2 will be launching worldwide on November 20th.