Hmmm... I suppose one could use the tools supplied

Fire up Active Directory Users and Computers
By default it should locate the Forest and Domain your on.

Then right click FIND
Then in Find drop down list select Organizational Units
Then in the IN: select your Domain or Entire Directory
Then in Named: Type in the name of the OU you want to find.
When it is found Double-Click it then go to OBJECT and it should
display the Canonical name of the object which is the path to that OU

I would assume this is not an on-going task, if so, why do you need to search for an OU so often in script? I'm sure it can be done via KiXtart and ADSI if one really has to, just curious why as I've been doing this for a while now and don't recall having to search for OU that often.