Althoug it will require you to have access to your webserver's log file it is extremely easy to setup and does nto require any special software. Basicaly if you can run UBB you can run this.
http://awstats.sourceforge.net/ One of its featues is the abilty to purge the webserver log file once it does its calculations. I have mine setup as a CRON running every hour.
Saved me a ton of disk space.
