Convert the design to use floats for the two columns, as discussed in the aside "Positioning Rather Than Floating

try altering the masthead to fit visually with the change in sidebar placement.

Here's an ambitious undertaking: Turn the sidebar into a horizontal toolbar, complete with drop-down menus, using the techniques explored in Project 6. If you want to really go all out, combine the drop-down styles with the Sliding Doors technique discussed in Project 7, "Opening the Doors to Attractive Tabs," to create a really outstanding toolbar.