Games Workshop have put up pretty much all of the Planetstrike buildings and terrain on advance order on their website.
You can check out decent photographs of the blastscape craters, shrine of the Aquila (which is now confirmed as a previously unseen building NOT the Dark Angel fortress), the resin mines, bombs and booby traps and the strongpoint, defence network and outpost combined sets. The hoped for trench board to add to the realm of battle gameboard never materialised and the it turns out that the outpost and defence network just come with the basic gameboard.
There are also some second wave Space Marine models in the shape of the Landspeeder Storm (which the Blood Angels can't get - boo!), Ironclad Dreadnought and two special characters - Vulkan He'stan and Kor'sarro Khan.
I'm eyeing up the Imperial strongpoint (with two bastions and three Aegis defence lines), the landing pad, the blastscape craters and the mines, bombs and booby traps which will pretty much fill up my planned trench table.
Bring on the 4th of July!