Hello, and welcome
common terms:
OCC - One City Challenge. Use the search function to get in depth rules, but basically you can only build one outpost in an entire game.
PCR - Post count reduction. Your total number of posts is reduced by a moderator when this happens, usually by 10-50%.
DL - Double login with two Apolyton screen names. Hopefully you aren't one, as being a DL is a pretty big violation of the rules outlined somewhere in this place
Vel's Strategy Guide - excellent downloadable and possibly even printed guide for both SMAC and its expansion, SMAX. Again, do a search on these forums to find a link.
general forum: IIRC (if I recall correctly), AFAIK (As far as I know), IMO (In my opinon)
Anything I forgot, just ask. Have fun.