I wanted to post this one, because I couldn’t find too much info on it. Actually, the SP1 help file still advises you to use the old method for assigning a static port to the Address Book service.
Exchange 2010 RTM
The Address Book service uses port 135 and the dynamic RPC ports (1024-65535). To force the use of a static port for the pre-SP1 service, you would edit the microsoft.exchange.addressbook.service.exe.config file, located in the bin folder:
Amend the RpcTcpPort value to your selected static port (which must be different from the one defined for the RPC Client Access Service).
You must restart the Address Book service for the new settings to take effect.
Exchange 2010 SP1
In SP1 this method changes to a registry key, in keeping with the method to modify the RPC Client Access service. What this means, however, is that if you implemented this change in RTM, then applied SP1, the setting is lost and must be manually applied again using this new method.
In registry editor, navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\MSExchangeAB and create a new key named Parameters.
In this new key create a new String value (REG_SZ) named RpcTcpPort and edit the value to be your desired static port (again different from that assigned to RPC Client Access)
Restart the Addres Book service.