Thanks all! Nope, there is absolutely no pattern to the dogs she picks on. They range from a Corgi to a Golden to a black Lab. Most were male, but I think one of them may have been female. I don't think it's a gender issue, though.

Ohh, I never considered the fear stages, Glacier. But that's really weird because she doesn't act submissive or shy. In fact, I think she's actually coming out of her shell. I was thinking about enrolling her in puppy ob. classes for the socialization, but I've seen some pretty incompetent trainers and I have a feeling she'd be deemed "dog aggressive". We're starting a pre-agility puppy class next week, though, and I'm starting to take her to puppy playgroups on the weekend.

We took her to the dog park today and she did okay. She did have one incident though. Again, she was fine with the dog until I came near her. Then, when we came back home, my neighbor's dogs were sitting outside their house (on lead). I decided to try to desensitize her and walked her until we were about 20 ft away. She started tugging on the lead and growling maliciously. I'll try using my body as a barrier, but I don't know how I could put myself between her and the other dog without working her up.

*sighs* In the meantime, I've been talking to a trainer and we're seeing what can be done to curb this.

ETA: Oh, right, the protection issue. I was also thinking that and the incident at the dog park today really reaffirms my suspicions. How would I go about curbing that protective instinct, though?