Here's a tool I use:
http://www.123promotion.co.uk/ppc/index.php
And yet another:
http://inventory.overture.com/d/sear...ry/suggestion/
One thing that worked for me is to do a search on the moderate (Traffic wise) keywords and optimize for them also. I found some real gems this way.
Another tool I use is this (When the site is actually up lol):
http://www.webmasterbrain.com/common...ool--tool3.htm
Common misspellings. I was amazed at the traffic I received, optimizing for common misspellings. There is/was actually a HUGE market for the purchasing of, 'Domain Misspellings".
These are also excellent tools for our PPC search engine campaigns.
Hope this helps.
Paul