Abby's doing a great job of training herself.  Seriously, all we do is praise her when she goes and she does the rest.  A couple weeks ago, she was playing in her room naked after having just taken a bath when she went running to the bathroom.  The entire time I'm in there with her she's chanting, "Peepee woom, peepee woom."  I could clearly hear her peeing in the toilet, so I was confused and asked her to show me when we were done.  Sure enough, she takes me right to a spot on the floor.  Apparently, she'd started to have an accident but stopped herself and went to the bathroom instead, so there were just a few drops on the floor!  That's the last accident she's had.  
We've now graduated from walking around completely bottomless to wearing panties accident-free in the last few weeks.  When we're home, she spends about half her time in just panties and the other half in a diaper and pants, but she's spending more and more time in panties.  I usually put her in panties until she decides she no longer wants to wear them and brings me a "big girl diaper" (Pull-Up).  As long as she's not wearing pants, she can work the Pull-Ups in the bathroom too.  She now insists on being changed the second she pees in a diaper, so it's much easier to put some panties on and let her use the toilet.  
I did try to put her in pants and panties last week once, and she did well for awhile.  Until I had to change her clothes twice in a half-hour period.  Then it was back to diapers.  I tried again this morning, and it went much better.  No accidents!  When she wakes up from her nap, we'll try again.  I'm still terrified of taking her in public without a diaper on.  We'll wait until she can comfortably wear pants without accidents for awhile before trying that.  Until then, she's pretty much house-trained already.