Why do you think that it took 2 years to get Skype on the iPhone?
Because Skype's been too busy with their thumb up their ass trying to figure out how to "monetize" Skype-to-Skype calls over 3G for the iPhone. And, as others have pointed out, Skype has been available for some time on the iPhone, they've just restricted it to only working over WiFi up until now.
AT&T lifted the 3G VOIP restriction months ago and Skype should have been able to release an update the day that AT&T did that. After all, it requires MORE code to check if you're on a 3G connection and display an error message. When there are no restrictions you don't need any code to check what type of connection you're using you just use the data connection without regard to where it's coming from. But no, Skype sat on their asses trying to figure out - Hey, how can we get iPhone users to pay us more money? Then some conceded dumb fuck said - I know, let's start charging for Skype-to-Skype calls over 3G, that will get us making some money.
Yeah, the service that's always been free for any other computer, phone or any other device. Skype's going to start charging us for the 3G data plan that we're already paying for. Well, I'm sorry Skype but you can go fuck yourselves if you think I'm going to pay you for that.