This video describes how to create a new license key in PowerCenter 9 and associate any existing services in the domain to the new license key.
How to automate the repository and domain back up process for disaster recovery in PowerCenter
How to unassign services from an expired key and assign them to a valid key in 9.1.0 and 9.5.1
How to find in which host the Repository Integration service is running in a multi node domain