I am looking for some ideas as to what tools to use in "conceptual design", and how is it different than logical design.

Definition of Conceptual Design:
- defines the busines problem and overall functionality of the system

Tools for building a conceptual design:
- possibly a paragraph or several pages of text from an interview with the users desribing the functionality of the system
- use cases and use case diagrams

Any references to books, websites or threads appreciated.