FireStats

FireStats is just like Google Analytics, only it can be hosted on your own servers and keep traffic data away from Google's prying eyes.

There's an assisted installation wizard to help new users out and a pretty insightful dashboard where statistics can be inspected.

FireStats can track various details and can be deployed to follow and log various website written in various programming languages or frameworks.

Can track websites written in:
HTML
Stand-alone PHP
C#
Django
Drupal
Gallery2
Gregarius
Joomla
MediaWiki
PHPBB
Trac
WordPress
WordPress MU

Can track:
Recent referrals
Popular pages
Search engine keywords
Browsers types
OS types
Origin countries

FireStats is free for non-commercial projects. But if using it on a commercial website, a license needs to be purchased.

Features:

• Installation wizard
• Multi-user accounts
• Follow multiple websites
• Grant access to users only to on website's stats
• Works in real-time
• Raw log access
• IPv6 support
• Possibility to exclude pages, users, IPs or user-agents
• Automatically archives older data
• Ajaxified dashboard UI
• Language packs for easy localization

What is new in this release:

• Fixed "Invalid site id" regression bug.

Requirements:

• PHP 4.2.4 or higher
• MySQL 4.0.17 or higher