The Operations Manager 2007 180-day evaluation version downloadable from http://www.microsoft.com/technet/prodtechnol/eval/opsmgr/default.mspx can be upgraded to the full volume licensed edition without the necessity of installing new binaries.
In order to update the license key (the only procedure requried), you will need to purchase a volume license key and then download the full licensed edition from the Microsoft Volume License Services (MVLS) web site https://licensing.microsoft.com
The volume licensed ISO CD image of Operations Manager 2007 contains LicensingWizard.MSI in the appropriate platform folder within the SupportTools folder.
Run the LicensingWizard.MSI on the Management Server currently running the 180 evaulation version will allow the product to be converted to the full version.
A KB containing this information will be available shortly.