

This presentation, by hjc New Media, shows the advantages to integrate usability and analytics efforts. It starts by presenting an introduction to the field of web usability, why it is important, and its Return on Investment. It goes on to provide an explanation of Web Analytics and a few case studies on what/how to measure and improve websites.
One free usability/analytics tool he doesn't mention is Open Web Analytics (http://www.openwebanalytics.com). It's open source and provides full click heatmaps, mouse movement/keypress recording and playback.
Great for real-time usability and ongoing tracking.