How to develop an RFI for SAP 4.6c to ECC 6.0 migration

We are planning a migration from 4.6c to SAP ECC 6.0. We are developing an RFI for this. Could you direct me to information regarding this?

The best place to start is the ERP upgrade portal accessible at http://service.sap.com/erp-upgrade. It contains links to many presentations, templates and documentation on the upgrade to ERP ECC 6.0. It is an interesting starting point for both technical and functional people.