I just wanted to post a warning for others. With my iBook G3, AppleCare replaced the battery for being under a 1-hour charge after 1.5 years. My iBook G4 was in the same boat after about a year but I hadn't gotten around to phoning about the battery until 1.7 years. Big mistake, call before 1 year is up.
According to the terms and conditions of AppleCare, batteries are not covered for notebooks after 1 year, even if you buy the 3-year warranty. They shouldn't have replaced my battery last time. I live in Canada but I called the US # by mistake today. She was quite happy to replace it, unaware of the policy, but then when she found out I was in Canada I had to call the other number. He knew the policy and refused to replace it. I verified the policy and he's right, it's not covered. Arg! $159.