phpOpenTracker is a framework solution for the analysis of Web site traffic and visitor behaviour. It features a logging engine that, either invoked as a Web bug by an HTML image tag or embedded with two lines of code into your PHP application, logs each request to a Web site into a database. One installation can track an arbitrary number of Web sites. Through its API, you can easily access the gathered data and perform complex operations on it (for instance, the analysis of your visitors' click paths).
polliwog is a Java-based Web server log file analyzer. It creates a Web site of statistics and information about your Web site. It provides you with detailed knowledge of what your visitors did while visiting your site. It provides information on human visitors (including daily statistics), searches, search engines, site areas, pages, visit paths, linking sites, and more. It is highly configurable and user-extensible.
Logfilter is a tool for performing ad hoc analysis on Apache log files. Logfilter is especially useful when you wish to find records matching very specific criteria, since you can specify exactly which fields to match. The tool also plays well in a Unix environment by accepting input either through files or via stdin.