Google Analytics makes it easy to improve your results online. Write better ads, strengthen your marketing initiatives, and create higher-converting websites.
Extract from Google Analytics at Google Analytics

I’m a huge supporter of Urchin/Analytics for the gathering and active management of critical web statistics for client SEM activities.

This article covers integration of the Analytics script into your WordPress blog or site.

1. Download Google Analytics WordPress Plugin v1.1 from taking the red pill
2. Extract and enable the plugin as standard practice; upload the plugin to /wp-content/plugins/... and enable it through the Plugin Management page within WordPress Administration
3. Open the Google Analytics Options page within the Options section of the WordPress Administration
4. Set the value of the Google Analytics profile to the value of _uacct variable defined in your Google Analytics account (eg. “UA-896702-1?)

The plugin will then add the necessary code at the right position in the HTML header of your blog’s pages.
Extract from Google Analytics WordPress Plugin at taking the red pill