Phosphorus and Lime

Ok, finally figured it out.

After you've filled out the first form. You must:

1. Select "I have an email address and password I already use with Google services like Adwords, Gmail, Orkut, or the personalized home page."

2. Select "I'd like to choose a new login name and password just for Books."

3. Use a non-Gmail email address to set up a new account

Getting started is easy. Once you know what you're doing.