Found a cool and easy to use log analyzer tool named WebLog Expert, it’s available in a free edition and an enterprise edition. It’s fast and it can generate some nice reports from IIS logfiles.
WebLog Expert is a powerful access log analyzer. It will give you information about your site’s visitors: activity statistics, accessed files, paths through the site, information about referring pages, search engines, browsers, operating systems, and more. The program produces easy-to-read HTML reports that include both text information (tables) and charts. View the WebLog Expert sample report to get the general idea of the variety of information about your site’s usage it can provide.
Another recommendable log analyzer is Awstats, which I’ve mention before.