WoodLog is a CGI written in PERL that opens YaWPS stats.dat file (where all the unique accesses are stored), parses its content and displays it with a good GUI.
WoodLog lets you select the date Frame, which browsers and OS you want to be viewed.
WoodLog is full customizable and very easy to install.
If you think YAWPS basic stats are not enough, download WoodLog and take ALL the control over your portal!