Kit creating is not so complex. Generally it covers editing of "text" tables and spell editing. But depends on your demands - they can do the kit creating difficult.
You can find tutorials about kit creating/distributing here:
http://members.blackwyrmlair.net/Chevar/tu...viewtuts&type=5For both editing (tables, spells; btw tables can be edited in normal text editor) I'd recommend
DLTCEP.
Near Infinity is alternative tool for editing.
If you are thinking about the distribution your kit public you should take a look to
WeiDU (see the bottom part of the main page).