Over the past few years, I've bookmarked quite a few useful SEO tool links. All of the tools listed are very easy to use, the only one that requires you to create an account is Google Analytics, but it's sooo worth it, enjoy!

1. Search Engine Submission
Submit your website to a number of search engines in one single step.

2. Google Analytics
Powerful, flexible and easy-to-use features now let you see and analyze your traffic data in an entirely new way. Discover who visits your website, where they found your website and how long they spend on your site. Even which pages they visited and which city they live in.

3. Website Grader
Grade your website's SEO level. This website is great, it will analyze your website in under a minute and make suggestions as to how your SEO level can be improved. It will even give you a score out of 100.

4. Keyword Density Checker
Just type in your website address and this tool will crawl your site and count the number of times each word or phrase is found. It will even calculate your keyword density, 2%, 3%, etc..

5. Competitor SEO Comparison
Compare your SEO level to your competitor including word count, image count, link count and tag analysis.

6. Search Engine Spider Simulation
Amazing in depth detail about what spiders see when they crawl your website. Spiders are the information gatherers for search engines. This tool will not only show you how a spider sees your website, it will also give you suggestions about improving your score.