There are a lot of SEO or Seach Engine Optimization tools out there in the internet. I would recommend the following.
- SEO Book has a keyword suggestion tool that allows you to find alternative keyword suggestions and even shows you the estimated monthly traffic on each word. This is a great tool and I use it all the time.
- The other site that is really good for information on SEO is called SEO chat. They have a ton of tools that you can use to optimize keywords.
- My third suggestion is you read a book called Search Engine Optimization An Hour A Day. It is a great book to help you understand how to build traffic to your site.