There are plenty of SEO companies available in online.You need to choose the best one.It is hard to find the best SEO service provider.I would suggest some points to select best SEO provider.
1.Search in Google or Yahoo for SEO search.
2.Select five providers among them.
3.Compare those providers with each other.
4.Read reviews about them and customer rating of the companies.
5.Find out the company existence.
6.Consider their SEO services,plans,features and price.
By following this simple points I have found the site http://www.tucktail.com/search-engine/seo-services.aspx?ci=1808&prog_id=447401
as they are providing the best SEO service world wide .