What we used to train Pixie (don't laugh) seemed to work great with one minor flaw:
We got the Puppy Diaper from Petco (roughly $20, but it's cloth and totally washable and reuseable).
I know it sounds totally stupid, but it really does work. She has to sleep with us at night (else she screams all night), but would occasionally have accidents in the bed. We finally got a puppy diaper to try it after trying everything else we could.
Here's the result:
She peed in the diaper ONCE.
We let her sit in it for about 2 minutes (long enough for her to realize that she didn't like that, but not long enough to totally abuse her). Then we took it off, washed it, and she has never peed in it since.
We had such a good outcome with it, that we used that to assist us in training her in the house. If she didn't pee outside when we took her, we'd put the diaper on (if she peed, she didn't have to wear it). She was so adamant about not peeing in it, that she learned quick that she could tell us to take her outside. And besides, when she did have that one accident, it was totally contained to her and her diaper. It was fabulous.
The downfall? She doesn't associate "poop" and "pee" to be the same thing. She almost always pees outside now without the assistance of the diaper, but she doesn't quite realize that she's supposed to poop out there, too. She WILL poop there, but if she's in the house and needs to go, she goes.
Luckily, she poops once a day and it's very small... so it's not THAT bad. We're still working on the poop concept.