Help! My dog is feral.

My little pound hound has a major attitude problem when she is on the lead.
She's not much bigger than my ankle but when she's on the lead and she sees another dog she goes nuts. Off the lead at the dog park and so on she is ok. She's not super friendly but she does a bit of a butt sniff and then walks off or she might have a play if she's in the mood. When she stays at the dog hotel or with my brother she gets on fine with the other dogs.
If she sees another dog while I have her on the lead she puts her hackles up and barks and growls and carries on. If someone brings their dog over to meet her she will snap at the other dog unless I tell the other owner to stay away. Today a big boofy brown dog came up wanting to say hello and she bit him!! :redface: Yep! You read correctly. She bit the poor, big boofhead's cheek.
Is there anything I can do to make her mellow out a bit? I'm sick of it.

My boofhead is the same :(. He's hopeless with other dogs, especially when he is on a lead. It's like he says "Let me at 'em, let me at 'em!".

I recently spoke with an animal behaviourist from the RSPCA we met at a park (while walking said boofhead) and she suggested bringing treats on walks (like dried liver or something else super-yummy for dogs). When you see a dog in the distance, bring the treat out and show it to your dog. Your dog will hopefully pay attention to the treat and not the approaching dog and eventually your dog will learn to chill out around other dogs. We haven't tried this yet :redface:. Our neighbour walks him daily so I haven't had a chance to try it out!

My favourite way of teaching a dog to behave on lead is to go to an off leash park, walk around the perimeter and stop and use treats to get your dog to focus on you, "sit","stay" "look" etc etc.... then move closer... pause when you get to dogs that are at the fence.... if your dog reacts, turn around and walk away... start over again until you can get next to the fence and your dog is happy to be close to other dogs. Generally, alot of the opposition to other dogs has to do with protection, if you were off lead it would all work, but if that is frustrating for you (as it is for me!) get them to obey before putting them in the stressful situation, and then inch your way closer until they behave in an acceptable way for you.