Microsoft on Tuesday released a free search engine optimization (SEO) tool for Web sites.

The software, called “SEO Toolkit,” works with Web sites supported by Microsoft’s Internet Information Services Web servers on Windows-based machines. According to a Microsoft spokesperson, “the SEO Toolkit does need to be run on Windows, but it can be pointed at and analyze any site — Apache or IIS — regardless of what it is hosted on.” It was previously released as a beta back in June.

The SEO Toolkit crawls through local and external Web sites and checks for problems such as broken links, slow-loading pages and invalid markup. It can be used to optimize key words to improve Web site hit counts.

 The SEO Toolkit manages site maps files, which search engines use to grab URLs. It can also check which URLs get excluded by search engines via a “robots exclusion module” that checks robots.txt files, according to Microsoft’s description. It’s designed to optimize Web sites searched by Bing, Google, Yahoo and other search engines.

To install the toolkit, Microsoft’s Web Platform Installer needs to be used. The Web Platform Installer centralizes the installation of Microsoft software used for Web sites. It’s also a free download available from Microsoft.

The SEO Toolkit will run on Windows Vista, Windows 7, Windows Server 2008 or Windows Server 2008 R2 operating systems. It can be downloaded at this Microsoft Web site, which provides support materials and a demo.