Most people agree that you shouldn't begin potty-training your child until she is ready. But how do you know when you're child is ready? Here is a brief questionnaire that can help you answer this question.
1) My child's favorite book is:
a. Goodnight Moon.
b. Green Eggs and Ham
c. Toilet Training in Less than a Day
d. Twilight
2) My child's favorite snack is:
a. Cheese
b. Candy
c. "Poop Yogurt" aka Activia
d. Laundry detergent.
If you answered C to both questions, your child is ready. If you answered D to both questions, your child needs psychological help.

The story behind this picture is that I had borrowed the book from one of my friends. The system described in the book is a very intensive day of training, and I was planning to do it with gusto. However, it seemed like the big day just kept getting pushed back. Then one day I turned around and Lily was flipping through the book, "reading" it to herself. That night she asked Alec to read it to her instead of reading a princess story. Which gave me an idea--I'll teach her how to read, then she can just do it herself!
Long story short, the day went very well and she has been using the potty ever since. I think the system is well-designed and based on solid behavioral principles and I highly recommend it to anyone who dreads potty training as much as I do. That being said, it also had the added benefit of providing some humorous reading material. After describing the system, the authors describe a training scenario--complete with the mother's ruminations. Here is an excerpt for your reading pleasure.
"Her hopes were soon realized. She had just given Mickey a drink at one of the dry-pants checks and was setting the glass on the table when she saw him walking over to the potty chair. He pulled down his pants and sat on the potty. This is it, she thought, he is going to the potty by himself. Then began the sweetest sound she had ever heard. "Pee-pee, potty!" he said. Her heart skipped a beat" etc. etc.
Practical advice and a literary masterpiece in one book.