Anteater is a log analyser for MTA logfiles (such as those produced by sendmail and postfix). The tool is written in 100% C++ and is very easy to customize. Input, output, and the analysis are modular class objects with a clear interface. Currently, there are modules for reading the syslog format of sendmail and postfix that do up to eight useful analyses and write the result in plain ASCII or HTML, to stdout or to files.
Advanced Web Statistics (AWStats) is a free powerful Web server logfile analyzer (Perl script) that shows you all your Web statistics including visits, unique visitors, pages, hits, rush hours, search engines, keywords used to find your site, robots, broken links, and more. It works with both IIS 5.0+ and Apache Web server log files as a CGI and/or from the command line. It also supports multiple languages including English, French, Dutch, Spanish, Italian, German, Polish, and Greek.
BBclone is a PHP Web counter on steroids which displays individual logs as well as aggregated data. It is a clone of Big Brother webstats, except that it is written in PHP and it relies only on flat files (no database needed). BBclone enables any Web site administrator to have a very precise view of who visit the website: OS, browser, date, referring page etc. Main features include reload resistance, hostname resolution, proxy workaround, and blacklist.