Question re-signing updates(and other rom zips)

i used to have a script for this and it was on one of my ubuntu boxes but for the life of me i can't remember which computer/partition/user it was under, and now i can't find the thread that i ripped the instructions for. if someone could point me in the right direction(preferably a thread link or thread title or better terms to use in search) that would be greatly appreciated, i am looking to tweak one of the current builds for personal use and i need to know how to resign before i can test it.

no i have no intentions of being a ROM dev, i just want to be able to tweak what the devs put out by throwing my faorite apps in as well as removing useless junk that i don't want/need
XDA has become a playground for morons and script kiddies