AWStats is a free powerful and featureful web server logfile analyzer (Perl script) that shows you all your Web statistics including visits, unique visitors, pages, hits, rush hours, os, browser's versions, search engines, keywords, robots visits, broken links and more...
Works with all major web, wap, proxy servers and some mail and ftp servers. Works as a CGI and/or from command line.
Distributed under GNU General Public License.

Web Statistics Montage is a free tool that compiles web statistics from multiple web sites and sends them to you in an easy-to-read, easy-to-compare format without having to log in anywhere! Just set up a simple configuration file, upload the files to your site and you're done.