Can my iPad 2 case fit the new iPad

I have ordered the new iPad and wonder if any iPad 2 case would support the new iPad. Is there a huge difference between them? I just want to save money by reusing my old Portfolio case, or I should just wait for what comes out.I think some do and some don't. The new iPad is slightly .03" thicker than the iPad 2 and a little thinner than the original iPad. If the case is made of hard material, it