Microsoft's Skype communications apps for iPhone and iPad have been updated to version 4.2. New features include the ability to chat with Messenger, Hotmail, and Outlook.com, and merge them all together into one, happy, mega-Microsoft account. If you're a first timer, you can now create an account from within the app.
You can also tap and hold to edit messages now, choose emoticons while typing, and -- terrifically or horrifically, depending on your point of view -- use animated emoticons in full on Retina quality. (I'm firmly in the latter camp -- I'd pay good money for a Skype update that killed animated emoticons dead. For everyone. Because, my eyes. My eyes.) There's also the usual round of bug fixes.
If you haven't used Skype yet, it remains much like democracy -- terrible except when compared to everything else. It's cross-platform, more reliable than most, and enjoys full background access on iOS (though keep an eye on your battery while it's active). If you're already a Skype user, it's a no-brainer update. Go get it.