Building Effective Teams, Handling Performance Issues

Scenario: The teams you are establishing need to have a way to deal with a poor performer. The basis of performance is to measure against agreed-upon objectives and to have periodic reviews during the course of the year. If a person's performance does not meet the expectations, some communication will be needed to get the person back on track.
Problem: Working in the setting of a global team, how would you as the HR Manager advise team members to deal with a performance problem? Include a number of the following items as well as issues you may add from your own experience: who would speak to the person - would it be an individual or a group; how would data be gathered on the poor performance; who would it be gathered from - other team members, customers; who will monitor improvement?

Explain how you think this should be handled.