AwStats is a pretty good tool to use for analyzing IIS web server logs. You can analyze IIS logs with AwStats by using the IIS access and error logs in a similar manner as to how AwStat works with Apache web server. Just make sure that you are using standard log file format with IIS. One way to do this is to enable CGI for IIS and create a script to run AwStats against each log file, if you are going to automate the process. The other way is to use a file copy script job to AwStats location and then kick off the analysis script. Please keep on checking this page as I will add a link to a complete tutorial on using AwStats with Microsoft IIS.