Skype has released Skype for iphone and iOS5 devices v3.5.454 that includes bug fixes and improved stability on iOS 5. Skype for iOS 5 is available free for download via App Store link below.
Latest Skype app for iOS is compatible with iPhone 4S, iPhone 4, iPhone 3GS, iPhone 3G, iPod touch 4G, iPod touch 3G, iPad 2 and iPad.
Download Skype for iPhone and iPod Touch
Download Skype for iPad