AWStats is a short for Advanced Web Statistics. It's a free powerful and featureful tool that generates advanced web (but also ftp or mail) server statistics, graphically. This log analyzer works as a CGI or from command line and shows you all possible information your log contains, in few graphical web pages. It uses a partial information file to be able to process large log files, often and quickly. It can analyze log files from IIS (W3C log format), Apache log files (NCSA combined/XLF/ELF log format or common/CLF log format), WebStar and most of all web, proxy, wap, streaming servers (and ftp servers or mail logs).
RobotStats is a free application analysing the web robots visits on your site. For each page of your site, a small PHP code allows RobotStats to detect if the visitor is one of the 180 robots supported by the application. In this case, the visit is recorded in a MySQL data base.
Visitors is a very fast Web log analyzer. It can process up to 150,000 lines/second of logs on a modern PC, outputs statistics in plaintext or HTML, and can be used interactively in a pipe with less to just see the stats quickly, or run via cron for the HTML output. It does not require any kind of configuration, nor to know the format of the Web log file to process. Can do visial web path analysis with graphviz.
Geo-IP enables you to easily look up countries by IP addresses, even when reverse DNS entries don't exist. There is a free database that is updated yearly, and there are a number of open source APIs available.