Apple has put up a web page showing "death grips" for a collection of smartphones, including their own iPhone 4. At first I thought this would be a bad thing for Apple's image, like politicians getting into a mud-slinging competition, where everyone comes out dirty, but their web page is well done.
One thing I have to say though -- nobody on a phone call is really going to hold the Blackberry, Droid X, or Nokia N97 as shown in Apple's pictures. Unless you're using the speakerphone, it would be impossible to hold the phones as shown and talk on the phone at the same time, as your palm would be covering up the microphone. So I think these images are a little misleading. To be fair though, they also show the iPhone 4 death grip in a way that would also make it impossible to talk on the phone, so at least they are consistent.