Anybody know where I can get good keyword analysis for a website for little or no expense?
I have four websites and want to optimize them for major search engines.

I have four websites and want to optimize them for major search engines.
I am trying to test a trial version of NetDog. It is working to block typed in URL's in Firefox, but when I do keyword searches, I can still access sites that I would think should be blocked (porn, etc.). How do I get it to block inappropriate searches for my kids?
Please be as spacific as possible.
For example, if I want to see how much a listing in the first five links for "teacher" costs, at Google or at Yahoo, is there a free tool that will show me what people are paying for those spots?
… Google didn't want to help this time!