Ideas for testing domain names?

Hi,

In his book, The Four Hour Work Week, Tim Ferris talked about quickly and inexpensively testing the title for the book using Google AdWords. I understand I can't use different domain names in AdWords, though, without actually creating different websites. What other ideas do you have for testing domain names?

I'm new here and haven't found this topic if it was discussed before, so feel free to point me there if I missed it.

Thanks for any tips.

Happy trails,

Judith