Actually, Sony has a contract with Skype to provide service to its "portable" game systems, making sure that Skype comes to every portable game console as long as the contract lasts.
The app will be free, and is available for download for the PS Store. It offers voice calling and video calls using the Vita’s front and rear cameras. It can also run in the background and alert PS Vita users when they have a call coming in. Note that this does not work with some PS Vita games (examples are Uncharted), as Uncharted disables all wireless connections, effectively disconnecting Skype.
Below is a video from video game legend Fatal1ty giving the run-down on the features.