proxy-report.pl generates a list of requested server addresses (simplified URLs) from your Squid proxy server log files. Requests for each URL are summarized on a per day basis. This script can generate reports based on the IP of the user. It also automatically handles gzipped files. URL exclusion patterns are supported. A sample report is available on the home page.
I have just installed it for our technical support center. It looks fine, feature-complete for our needs, and was defenetely easy to install.