So you can double-click on a TTable icon. That should open a small dialog window (assuming you have a connection and the database/name properties are set). If you right-click in that window, you should see a pop-up menu that offers (among other things) "Add all fields Ctrl+F." Selecting that should paste all of the TXxxxxxField references into your unit.
If not, do you have a client-server (or Enterprise) version of Delphi?
At least, that's the way it works in D5. If no one else comes up with an answer, I can review what happens in D4 after I get home tonight.