truing a wheel is to make it spin "true." straight, basically. it's not
that hard, if you know what you're doing. but it's a good way to make it much worse if you mess it up. you tighten and loosen spokes in order to pull the wheel from side to side.
it might be better to have a bike shop do it for you.
here's a link to show you what's up...
Park Tool Website
