Any Aussie experience?

We have a puppy, Molly, who is now 3 months old and we're still having problems with her being too "mouthy". She is half Aussie and half Viszula (he was just passing through!) and although she looks more like the Viszula her instict to herd all of us around is unmistakable. She has slowly develped a softer touch with her mouth, but it's kind of unnerving for other people, and hard on small children to have her nipping at your heels and legs as you walk around the yard. She's never actually bitten anyone, and when her sharp little puppy teeth are gone we won't notice as much, but I'm sure there are ways to work with herding dogs like this to help them learn to use this gift appropriately. Molly is a doll otherwise, and really smart, but when she gets wound up she can totally forget where her teeth are. I would really appreciate any advice. We've always had easy to train Golden Retrievers before, so this is a challenge, but I want to do things right for her sake as well as for ours.
Thanks,
Kathy

P.S. We do live in the country so she has plenty of room to run and exercise, and she does spend a good bit of time trying to herd our 2 big Muskovy drakes around the yard, although they mostly try to ignore her. We also have horses and chickens, but they don't need any herding either. Maybe I need to get a sheep and take up spinning.