According to ThisIsMyNext the iPhone 5 design will change to a more tear drop shape and look more like the iPod Touch than the current iPhone 4. Note that the design in the picture is not an actual reproduction but rather due to some fancy Photoshop work from the blogger. If you'd like to read more about what they are saying click on the link at the start of this post.
Interestingly, the blog BGR is indicating they expect an announcement (and potential release) for the new iPhone 5 as early as the end of August.
My phone contract comes up the end of summer, and I've already decided I won't be getting another BlackBerry. I've been debating whether I should go iPhone or Droid. Hmmm...decisions, decisions.