I have something similar called Cozip. link.....
http://www.cozip.com/
It is for the 2nd gen but they have them now for 3g phones. I really like mine because it makes the iphone feel unique. It just pops on and it protects the back from getting scratched up. It does not protect your phone if you drop it though. This is the only draw back. I have had many cases like most of us and i always come back to this one. I don't carry my phone in my pocket but rather on my belt. I just bought the sideways leather case from att and use that. It was a little tight at first but it has now stretched to fit.