POSTed is the name of the POSTAL 2 sdk/level editor that was included with Share the Pain. The name itself is commonly used to refer to both the Level Editor of POSTAL and the POSTAL 2 SDK.
POSTAL Level Editor Edit
Included in all disc copies of POSTAL, this level editor allowed players to customize existing levels. Unfortunately, one could not import their own art or create levels from scratch which made its inclusion a case of dead on arrival.
Steve Wik of RWS on the Level Editor,
"Again, don't ask. The damn thing is so complicated I don't remember the first thing about how to use it. And while making your own maps from scratch is theoretically possible, it requires a bunch of software that mostly isn't even made anymore and a bunch of in-house utilities that we lost years ago and the process is absurdly complicated and I forget most of it anyway, so move along, there's nothing to see here..."
POSTed: POSTAL 2 development kit EditOriginally bundled with Share the Pain, POSTed is a modified version of Unreal Editor 3 (Not to be confused with Unreal Engine 3 Editor) used to make mods for POSTAL 2.
Sharing many of the same features as the standard Unreal Editor, fully capable of building levels, compiling scripts, just about anything but the underlying C++ code is fair game. The current iteration can be found as part of POSTAL 2 complete and includes the Unrealscript Source files of POSTAL 2 Complete, Apocalypse Weekend, and (if you own it) Paradise Lost.