Let's be clear about a few things...
First, GIZMODO covered their butts quite well with documenting the interview with the person who found the iPhone and was given the phone as his or his friend's phone. Secondly, the finder of the phone contacted Apple and even has an Apple Care incident to document this internally with Apple, which I suspect was followed up with the email that we normally receive. Thirdly, why would Apple sue? They got free press; any follow up with a law suit makes it even worse and gives Apple a tarnished reputation; if it is the real deal then remember what our mom's told us... don't make it a big deal, too, and we won't make it a big deal, talk about being to trend market acceptance; GIZMODO did not take it apart officially and post pictures of the inner workings (no, they could have) and thus reveal confidential chip names, processors, etc.; they did not post images of the iPhone plugged into iTunes noting the OS4.0 which would have violated NDA's for beta release; and more things that I cannot recall right now.
GIZMODO dotted their i's and crossed their t's. They reported as much observed things as they could without opening, destroying, turning 'on', etc. the iPhone before its officially release in June. I think a lawsuit would be frivolous by Apple.
Finally, the iPhone is slicker, thinner, cooler (HD, better removable battery), more iPad like, and just is a nice update. Good design and kudos! I will be buying one once they are released.