Internet Explorer

Your question implies that you are a coworker doing a bit of sleuthing on your own. If so, I advise against any such action.

If you are tasked to monitor the use of systems as part of your regular duties and in support of your company's acceptable use policy, there are a number of tools available. A key reason that companies institute Internet policies is to make it clear to employees that the equipment, networks, systems, and data they use and create are company property, and that employees have no privacy (Overly, 1999). In order for an employee to win a claim for invasion of privacy, the employee must establish the expectation of privacy in the workplace. (http://tinyurl.com/6zle)

Some sample monitoring tools include log files onthe firewalls, and on the egress router if you are not using NAT. Monitoring application software for use on individual machines can be found at http://tinyurl.com/6zln or by doing a search at Google.