Usability
Usability testing is basically testing the ease of use for any given website. This would be seeing how easy it is to navigate and to find the relevant information that you are specifically looking for.
There are a couple of ways that you can conduct usability testing. First of all you could give your site to a colleague or find a group of people to test your site and give you feedback for improvements. The other way is to send it off to a company that tests sites for usability and they will give you relevant feedback for your site.
The main things to test in usability is the ease of use, this basically means to test the navigation for finding information. The other things that should be tested for is retention of information, content relevance, error rate and user satisfaction.
Resource in which you can use to test this would be friends, family and other web professionals. The other way to go about it is to seek professional assistance in forms of companies that usability test sites.
http://www.elementalcreative.co.uk/index.html
http://www.techsmith.com/morae.asp?CMP=KyahooM
