There are one of two real issues here:
1. Is the employee accomplishing sufficient amounts or high enough quality in his work efforts?
If not, deal with this situation on that level as a performance matter--advise him of his shortcomings, counsel and discipline (up to and including termination of employment).
2. The employee is doing a great job but you are annoyed by him breaking a company policy (showing at the very least some level of dishonesty).
If this is the case, presumably the employee has a supervisor. So, the old-fashioned but effect use of observation comes to mind. I would not go further than that.
One of these two ways will work, if applied.
Question added to topic Human Resources • December 12, 2009
How can I monitor my employees' time on social networking sites and personal phone calls?
The company policy clearly states that cell phones are not allowed during office hours, unless authorized by management. Our employees do not have access to the internet, but I am suspicious that several employees are using their cell phones to text and go on Facebook during office hours.
Penny is a seasoned human resources executive and consultant with over 25 years of diverse business experience in advising enterprise leaders on employment-related matters.