There are a few Skype apps in the App Store already, but none of them give you the full features of Skype like the official Skype app will. As you can see from some of the sample pictures you can check your Skype Credits, edit your profile, set your status etc.

For those of you unfamiliar with Skype, it is a Voice Over IP client that lets you make calls over wifi so you do not waste your cellular minutes. You can also call anywhere in the world for 2.1 Cents per minute.