The new ribbon feature in the PostalCAD 2009 interface fills up a good portion of the drawing window. After you have reviewed the ribbon and used it to a point where the learning curve is over and you are comfortable with where to find things, most users will then use it in a minimized state.

Here's a quick overview for minimizing the ribbon.

Click on the button with a down arrow to the right of the last ribbon tab to minimize the ribbon showing only the panel titles.
Click on the button with a down arrow to the right of the last ribbon tab when the ribbon is in the panel titles mode to minimize the ribbon showing only the tab titles.
Click on the button with a down arrow to the right of the last ribbon tab when only the tab titles are showing to maximize the ribbon back to it's original state.
These 3 ribbon modes have a learning curve to them also, so try each state several times and then decide which visibility state suits you best.