We are having issues with the neighbor's pit bulls. What do you suggest we do?

We have a problem with our 15-week old female GSD - or should I say, she has a problem with our neighbors pit bulls. Our little girl is a solid, stable, dream of a dog. She has displayed very sound temperament and good nerves from day one. However, I worry about negative effects from our neighbors pit bulls. We share our back fence with them, and at any given time, at lease one of their FOUR pit bulls is in the yard. We have never liked these dogs, as we were told horror stories about their escape-and-attack escapades when we moved in; and they are left to bark outside all hours of the day and night. As a dog lover, it breaks my heart to see the conditions they live in, but all our efforts to involve the police and/or animal control have failed. They had one dog removed and destroyed after an attack, but because the remaining four have not bitten anyone (YET), the authorities are unwilling to help.

My concern for my dog is this:

From day one our little female either ignored the pit bulls barking, or simply watched with mild interest. She never approaches the fence, but neither does she display fear. She just looks on, and then continues about her business. A few days ago, however, she had a scare with the pit bulls. One of the pit bulls was barking at her, which caught her attention. Her attention was focused on the barking pit bull, and she didn't see the second pit bull sitting outside her line of sight, until it stood up and began snarling. She turned and took a step backward to look at this second dog, and as she did so, backed up into a bush. The bush startled her, and she tucked tail, yelped once, and ran back towards the porch and my husband, the alpha dog. I charged the fence, yelling, and gave the fence a couple of kicks for good measure. Then I approached my dog, who had laid down next to my husband. She didn't seem particularly fearful or upset at the time- she's a pretty hard little pup- but since then she has been cautious about that area of the yard. I can encourage her into that area, but she'll stay only as long as I make her, and won't do so on her own accord.

I'm not concerned so much about her being traumatized by this one very minor event, but more that these vicious pit bulls (who really need to be destroyed, it'd be doing the dogs a kindness) may eventually create some incident that will screw my dog up. Is there any way to deter these pit bulls from approaching the fence so aggressively, and if not, what measures can I take to protect the dog from any negative effects from these growling, snarling monsters on the other side of the fence.

Your website has been fantastic, by the way. We (my husband and I) were so thrilled to find such a wealth of information that FINALLY confirms our beliefs and approach to dog training.

Thanks,
Tim and Alyssa