My 6 Month Old Male Aussie Is Biting My Kids' Faces. Help?

Just like it says. The dog is biting and I can't control it. He bit my nephews face when he tried to do something (I'm unsure why he was grabbing the dog in the first place). It seems like it is when the dog is super hyper and playful that he is biting. He does not bite me, my husband, the baby or any other adults. Just my two boys 5 & 6, even when they aren't doing anything to him. My nephew is the only other one he has bitten. So do I give up and just get rid of the dog? At this point, I'm so frustrated with him, I don't see how owning a dog can possibly ever be enjoyable. On the other hand, there are some days when things go well and I like having him. I generally like animals (used to work with them a lot) but this is SO frustrating! I need a real solution, fast!