Send a PM to http://www.atlantareefclub.org/forums/member.php?u=1900">Barbara</a>. She just had a terrible bout with nudis and I believe she's finally eradicated them. She should have some tips for you.
In the meantime, <u>isolate those zoas</u> in a Q/T or all the zoas in your display could get infested. I think you have to pick off the nudis and the eggs. It's quite a chore.
If you got the zoas from a LFS you might want to tell them (they may or may not care), but if you got the zoas from a member, definitely let the member know as a courtesy. They'll need to keep a lookout in their own display and take whatever precautions are necessary.
These things can be nasty. Good luck!