Visit http://www.tuelz.com/bigpage.html for more tools.

Back Link Analyzer -Here's a 100% FREE tool similar to Opti Link and SEO Elite, but it is free.

DLR Analyzer - "This tool was created to analyze how the deep link ratio of a site affects its rank in search engines. We can use this tool to compare the DLRs for the best ranking sites for a search phrase. For each phrase you enter, this tool will calculate the deep link ratio of the top 10 search results. A website's backlinks are the links to it from different sites. A website's deep link ratio is the comparison of the number of backlinks that go to pages under the top level of the website to the total number of backlinks for the entire website"

151 SEO Tools - A nice collection of seo tools, many free.

Copyscape - Check the "dupe factor" of content.

Similar pages checker - It sometimes doesn't load, I think because it's busy.

Webmaster Eyes - Here is a useful tool to give you a quick PageRank snapshot in the SERPs for a particular keyword phrase.

Advanced Google Searches - A very useful "google searcher".

The Google PageRank Value Report - will return the Google PageRank values for the list of urls you give it.

GoogSpy - Here's a new free tool that lets you search Google Adwords by keyword or by company/website. Here's a good intro article by Allan Gardyne explaining some uses for Googspy.

Visit http://www.tuelz.com/bigpage.html for more tools.