SEO Book (http://seobook.com/) is a site that offers SEO information, tools and services. Their primary intent is to sell you access to their online "SEO Book" product. This is, undoubtedly, one of the best SEO resources on the Internet and the free information and tools are worth your time even if you don't purchase their product.
Their free keyword research tool offers the following:
- Offers rough suggested daily search volumes by market for Google, Yahoo!, and MSN.
- Links the search volumes to the related global search results.
- Provides links to price estimate tools from Google AdWords. That Google AdWords tool shows the necessary bid to rank #1 for 85% of queries, and roughly how much traffic you could expect AdWords to send you based on that bid price and ad position.
- Links to Google Trends, Google Suggest, Google Synonyms, Yahoo! Suggest, and Keyword Discovery keyword research results.
- Links to various vertical databases like Topix.net, Google Blogsearch, and Del.icio.us to let you know if people are talking about your topic and what types of resources they are referencing.
- Is driven off the Wordtracker keyword suggestion tool. If you sign up for a Wordtracker account they offer many additional keyword research features and tools that are lacking in our basic keyword tool.