There are a number of good resources on this topic. Perhaps the most famous resource would be the book, "Don't Make Me Think". This is a topic that would benefit business users, developers, and designers. There are different ways to do usability testing but the best solution I know of is with the Morae software. Don't fail to do usability testing if you don't have this software. This is one of the most valuable practices in web development.
it the Morae website at http://www.techsmith.com/morae.asp.
It could be that this product is so good at usability that there doesn't seem to be a need to look for another solution. This product lets you record audio, video, and on-screen activity. This includes the keyboard and mouse input during a session. If you use the observer module, you can also make notes and flag tasks in real time. When the sessions are done, it has the tools to help analyze the results and deliver them back to the key stakeholders to make decisions about the state of the items being studied.