Apple has now mailed out about how to get your free iPhone case. You can get it if you have had connection issues, but you're not asked to put your hand on the bible or copy of Dracula about this, so I imagine many people will just like to get the free case. I'm tempted, but I already have a case I like.
Here is a review of one of the offered cases, the Speck Fitted. It looks very nice. (BTW, what does the reviewer mean when he talks about "flash" here?)