hello this is my first post, i’ve been fooling around with zbrush for a couple of weaks and i like it alot. the manual is great! 
my question is, i have imported a model from Maya and while working by accident i forgot to press mirror x so now my work is for nothing. is there a way to mirror or clone it to the other side of a symetrical model?
Yes. Use the Tool>Deformation>Smart ReSym feature.
Simply mask the side that you have done your work on, and then use the feature with the proper XYZ switch active. What you sculpted on the masked side will be mirrored to the unmasked side.
Great, thanks aurick