Blenderhead: The 2-sided option in the Material Editor is just for rendering. To enable 2-sided polygons in the viewport, go to Object Properties, and then unckeck Backface Cull in Display Properties. (my first post here by the way... Hi everyone! Hopefully I'll start posting some 3d work soon :)
to build off of Shadowstep's response above, most game engines don't support non-power of 2 textures. you can have non-square power of 2 textures (a 64x128 for instance), but you would never see a 96 x 96 or 48 x 48 in professional game development.