The report can't tell you that. There is no way to access the ID from within the report itself.
I assume you're using Crystal Enterprise (CE) rather than BusinessObjects (BO). I'm not sure how to do this in CE, but in BO I would log in to the Central Management Console, navigate to the report and look at it's properties to get the ID number.
-Dell
A computer only does what you actually told it to do - not what you thought you told it to do.