04 July 2007
I think you are enquiring about the governing rules for taking cenvat credit of service tax paid on input services. If so, it is "CENVAT Credit Rules, 2004".
The difference between Cenvat credit on input and cenvat credit on input services is - credit on input is available as soon as the input is received in the factory where as credit on input service is available only on making full payment of the invoice.