In complement to Philippe's answer:
For Bill : yes, the Advance Steel viewer license allows you to open and see Advance Steel Models and all Drawings (only see / not modify).
For Greg: without an Advance Steel viewer license, you cannot see an Advance Steel drawing, unless the Advance Steel user has “exploded” his drawing to a standard DWG file. In Advance Steel, there is a simple command to “explode” all (or a set) of drawings as simple DWG. Then, they can be seen and modified by any AutoCAD or AutoCAD LT. But in this case, changes are not synchronized anymore with the model.