Since I've only listened to Tina reading the book, I'm going to encourage everyone to just listen to the audiobook. She's hilarious, it's hilarious and even includes the audio to her Palin SNL sketches.
This is an autobiographical book but really really really funny. Covering her childhood, touching briefly on the scar on her face, her time at Second City to SNL and 30 Rock.
Did I mention this is funny??
Read it. Or rather, listen to it.