With idea of @FurioATV & support of CNC I'm introducing you to in-appstore.com on OS X. Yes, Mac&Hackintosh have got free in-app purchases too.
Read Getting Started for OS X and enjoy!
PS: Apple, you forgot about your customers on iPhone 2G&3G. That's the right way.
PSS: Your turn.
Yes, I notified about developers' letter and fix of this problem. Let's wait for iOS 6.