Once its out of wack its going to be a b!tch to get set again, but it can be done.
Working on one cable at a time, move the adjusting nuts a few turns and keep in mind what direction you went and how many turns. Test drive it and adjust it some more if needed. You may need to adjust it in the opposite direction.
Go to
http://www.hmaservice.com/webtech/default.asp and look up your car. There is a good picture thats shows you what to look at as you're adjusting the cables. Look under Transmission/Manual System/Man Trans Shift Control/Components. You want to keep the botom of the shifter in the 'neutral' position, meaning equal distance on either side of the shift pivot. Hard to explain - look at the picture and you'll know what I mean.
Good luck.