The Client Operations Management License (OML) is for the management of clients and other devices not running server operating systems. Features include monitoring, troubleshooting, audit collection, and reporting for any client application, base operating system, system hardware, and other management agents on the system. 

Notes & Requirements: Operations Manager 2007 requires a Server License for each management server and an Operations Management License (OML) for each operating system environment.  A minimum of 5 OMLs is required.