WassUp is a Wordpress plugin to track your visitors in real time. It has a very readable and fancy admin console to keep tracks of your blog’s users visits. It has a “current visitors online” view and a more detailed “visitors details” view where you can know almost everything your users are doing on your blog, it’s very useful for SEO or statistics maniacs. It comes with a “Spy” view in Ajax like the Digg Spy. The aim of WassUp is the knowledge of what your visitors do when they surf your blog. With WassUp you’ll get a cronology of your blog’s visits with a lot of details for each single user session.

Pricing: Free
Requirements: Wordpress 2.2+
Source: http://www.wpwp.org/