Google webmaster tools provides a rich amount of information for search engine optimization & web analytics. For SEO, sitemap submissions help in indexing of all the pages & also errors associated with any pages can be found out. Crawler access can be set to index the pages. Top search queries & top pages help in optimizing the pages properly to get more traffic. Crawl errors help in identifying errors associated with pages & can be set right to index such pages. Links to the site provides backlinks to the site.
Now, Google has included google webmaster tools report in Google analytics. By linking both the accounts, one can easily access webmaster tools report in GA. This is available under search engine optimization in GA. Queries, landing pages & Geo summary are some of the info available which can be used for better SEO of the website.