How do you put subtitles on a movie in iMovie '08?

I made a music video in iMovie but the lyrics are kind of hard to understand. I want to know how to put subtitles on the movie, but that follow the lyrics. So if I am singing one thing, the lyrics to what I am singing are appearing underneath the video. Help help help!

Get to know them better. This is not a task only to be accomplished through dating. The more you get to know him or her, the more you can tell if you like them as a friend or something else. Just talk and do fun activities with the person.
Stop and consider why you like the person. There are many physically attractive and smart people out there. But if you see something beyond that really catches your attention, you've marked this person as unique and probably like them. Why else would they stand out from so many?
Consider how many times you think about the person. If you find yourself thinking about this person several times a day, and they are happy thoughts that possibly make your heart beat faster, then you probably like them.
Think how often you laugh at their jokes etc. When you like someone, you will find yourself laughing at things even if they aren't that funny. This is a natural attempt to make them feel appreciated.
If the one conversation between you and the person is stuck in you head and you cant stop telling people about it. this means it was important to you, and you probably like the person.
Consider how much you try to be near them. If you've planned your walking speed to catch a glimpse of them as many times of the day as possible, there is a good reason for that.
Think about how you feel if you touch him or her, by accident or on purpose. If you're still thinking about brushing shoulders several hours ago in school, then that is a special thought and you probably like them.
If you feel you're ready for a relationship, and are confident enough for a positive response, then just go ahead and ask them out. If you're unsure of their feelings for you, there are several wikihows on how to tell if someone likes you.