This post is a follow-up of last week post about SEO: Off Page SEO: Error 404. I invite you to read this previous post as well. If you would like to have a whole picture of my SEO guide, you can check the series from the very first post: Comprehensive introduction to SEO.
Google Webmaster Tools, Yahoo Site Explorer and Bing Webmaster Center
The main Search Engines are now offering tools to analyze the way your site is being seen by the Search Engine Spiders.
The most complete set of tools is probably Google Webmaster Tools. You’ll find a ton of useful information to optimize your site and tweak it to make it Search Engine Friendly.
You can also submit your sitemaps to get indexed faster, identify errors, and learn which keywords you are ranking for. You can also ask for a page to be removed from the index (very useful if some admin pages get indexed by error).