SEO Research Labs: Very good resource by Dan Thies.
SearchEngineLand: One of the top information resource websites on search engine optimization. These guys generally have the best advice that is usually published before other SEO news services.
Marketing Pilgrim: Andy Beal’s award-winning search marketing blog.
Search Engine Journal: Search Engine News on SEO & Search Marketing Optimization
Search Engine Roundtable: Very good SEO resource giving the pulse of the SEO community
SEOmoz: SEOmoz serves as a hub for search marketers worldwide by providing education, tools, resources and paid services to help make every SEO the best they can be.
S.C.O.R.E. stands for the Service Corps of Retired Executives, and they pride themselves on being Counselors to Americas Small Business. In effect, S.C.O.R.E. is a non-profit group that offers FREE consulting to anyone who has, or is thinking about starting a small business.
SearchEngineWatch: Loads of search engine information and research, a good place to start. They report the search engine news pretty well also.
Google Services: Wikipedia summarizes Google’s list of services quite well.
136 SEO Tools – Known as the Tool Place, you can find a whole range of terrific tools which will help you research and speed up your own search engine optimization campaign.
Here’s a decent link to some more useful free SEO Tools #2 to help in your search engine optimization efforts..
Digital Point SEO Tools: Including Link Value Analysis, Link Popularity Analysis, Domain Popularity, PageRank Check, SEO Challenge, SERPs Position, Outbound Links, Keyword Density, Cloaking Detector.