The upcoming "Steel & Titanium" pack will add two new maps to the game. One map, Wasteland Bullet, will feature fast-moving trains that players can hop on, and the other, Vetka Cruiser, is set on one of the ISA's big battle cruisers, the New Sun.
A bit of info about a second pack was also mentioned, and it sounds like this pack will have a retro theme, perhaps offering some upgraded versions of maps from the previous Killzone.
The first pack is due sometime this April. For more, check out the archive of GT's TV show.