Z.S.
Hi D.,
it sounds like she's almost ready. You have to see signs of readiness before assuming she is. Since she doesn't want to wear a diaper or underwear, that is one sign. Another one is if she's able to stay dry for a couple of hours like during a nap. If she expresses interest in becoming like mommy, then she'll imitate you. Even if she's not ready to sit on the potty, have her get used to being around it...at least she puts her dolls on it. Show her how the dolls can go potty too.
Just remember not to pressure her into potty training. When she's ready she'll show you more signs. I have friends that place the potty chair in front of the TV, while her kids sat on the potty and watched cartoons. Since this is summertime now, she'll want to keep her diapers and underwear off...it would've been the perfect time to start, but don't force her.
I have a DVD I'd like to suggest. It's called, "Potty Power for boys and girls." It's such a neat DVD. My son loved every minute of it and it shows not only how to go potty, but hygiene as well. I borrowed it from my local library. You can also purchase it online too.