yea, its not that hard (I believe there is a tute or two in Ed's depot).
Basically, you simply make whatever textures (in .paa format) and then
set up the proper codes for defining the crap in yer "description.ext" file.
In practice, its alotta defines (or coding or whatever ya wanna call it).
A quick way to get into the art of making cool INIT pics or similar stuff is to
DL one of the missions that already make use of this feature
in short: hit the mission depot - and take a quick search in Ed's depot as well.
And if you have any trouble underway, feel free 2 post back here
later