You could use the 2d commands (sprites, sprite collision, etc.), but that would slow most computers down considerably. Another option is textured planes that are positioned facing the screen. If you want a 3d type thing like where you pull up a laptop, you could just place the cursor on the face of the object relative to the position of the mouse.
Look at
http://www.robinking.com/magicworld to get the MagicWorld source code. That had a really slick menu system thing, and it was written in DBC.
Crazy Donut Productions
Current Project: KillZone