What is the relationship between Change Management, Project Management and Release Management in ITIL?

In IT parlance,

Change Management - simply known as introduction of any change in an BAU operating environment. This can be changes to a server, desktop, configuration of network equipment, introduction of a new server, link, network device, etc. Outside IT, Change Management has broader relevance and meaning in terms of Process changes, new product launches, people role changes, etc

Project Management - logical flow of tasks to achieve defined objective eg: Migration of windows xp to windows7 can be pursued under project Management. Any project Management will usually have underlying change management.