Managing Change Management

Change management is a big management topic with lots of researches and writings. Here is an introductory writing:

Change management can take many forms and include many change environments. The most common usage to the term refers to organizational change management.
Organizational change management is the process of developing a planned approach to change in an organization. Typically the objective is to maximize the collective benefits for all people involved in the change and minimize the risk of failure of implementing the change. The discipline of change management deals primarily with the human aspect of change, and is therefore related to pure and industrial psychology.
Many technical disciplines (for example Information technology) have developed similar approaches to formally control the process of making changes to environments.
Change management can be either 'reactive', in which case management is responding to changes in the macroenvironment (that is, the source of the change is external), or proactive, in which case management is initiating the change in order to achieve a desired goal (that is, the source of the change is internal). Change management can be conducted on a continuous basis, on a regular schedule (such as an annual review), or when deemed necessary on a program-by-program basis.
Change management can be approached from a number of angles and applied to numerous organizational processes. Its most common uses are in information technology management, strategic management, and process management. To be effective, change management should be multi-disciplinary, touching all aspects of the organization. However, at its core, implementing new procedures, technologies, and overcoming resistance to change are fundamentally human resource management issues.

Here are a few online site on the subject for your easy reference:

Organizational Change in Project Management Wiki
Article on Managing and leading change initiatives
Summary of the key factors leading to resistance to change
Change Management podcasts