Pictors Studio has a tutorial on building bug tunnels for your Starship Troopers games. They are constructed out of pink insulation board and look quite nice.
Here are some rules for using the Dirtside II system to recreate battles from Heinlein’s Starship Troopers.
Shock Force Starship Troopers modifies the Shock Force rules by Demonblade for the Starship Troopers film universe.
Kurt Bowker has written a set of free wargames rules set in the Starship Troopers movie universe. I’m not sure where you would get the miniatures to go with these — perhaps Ground Zero Games has something that could be used.