Usability Testing

Usability Articles
Jakob Nielsen - Usability Expert
Usability 101 by Jakob Nielsen
Misconceptions on Usablity by Jakob Nielsen
Usability Testing Demystified via A List Apart
Web Usability Test on TED

Online Usability Testing Tools
Survey Monkey (online survey tools)
Google Analytics (insight on how site is being used)
Five Second Test (usability test for design)
Clickheat (visual heat map)