Yuri started out on puppy pads, and only goes outside now. I slowly moved his pad a few inches everyday til it was outside where I wanted him to go then ditched the pad. You have to watch them pretty close and run them out to the pad, for a little while after moving it outside before they get the idea, but it worked for us

it didn't take long for him to start telling us he wanted out. He seems to prefer it outside
You have to speak Yuri to understand when he wants out. I plan to get Yumi a hanging bell and try ringing the bell when I take her out (they are supposed to learn to ring the bell when they need to go out), but we'll probably be puppy pad training for a while yet, there are too many loose dogs here to start outside before she has finished her shots. With my luck she'll just think it's a cool toy :P
Yumi is my 1st yorkie but I've heard they are really hard to potty train, so good luck