Jeff,

>>Developing the Conceptual and Logical Design

In addition to Evan's excellent explanations, you could think of the differences like this:

Conceptual - an overview of the project requirements from the customer's point of view or in terms that the customer can relate to. This includes WHO will use the system and WHAT the system will do, without specifying all the exact details of HOW the system will accomplish those things.

Logical - a more detailed analysis from more of a programming point of view, which should result in lists of entities and their attributes, their relationships to other entities, data integrity and relational integrity rules and constraints, and classes with methods and properties. At this point, there is still no addressing of physical details such as whether it's VFP data or SQL Server, etc. Just a logical design that can be translated into a physical implementation in the next step.