Freezing isn't a problem. Opinions vary on whether to add any liquid. Look on Google for 'pulled pork freezing' - loads of links. Pick the method that suits you best.
We freeze large amounts of barbecued pulled pork often. I can't recommend highly enough, though, that if you freeze much stuff and intend for it to last a fairly long time... say 6 months to a year, the reasonable investment in a vacuum sealer is well worth it. We use ours all the time...