my puppy has this problem.we are still in the learning phase and we tried the turn our back trick, that has no effect on her.
I saw a episode of victoria stillwells where she was helping train a jumper, she had a leash on the dog, brought in a visitor, and the dog jumped , the second the dog did this she took the dog out,(away from everyone) waited for dog to be calm, went back in the room, dog jumped , repeat. and after I think she said 10 minutes of doing this the dog finally stopped.
so I decided to do give this a try and it does work, only thing LOL is I have to do it to each individual person. Its almost like she says "oh well I cant jump on dad but hey this person is fair game"
this is why I said she is learning. This tech. definatly works, I guess it boils down to consistancy.
if we are out for a walk or something, I step on the leash, while she is in sit, so if she gets the urge, she cant jump.