With skype you can connect to others via instant message, audio conferencing and video phone. It can also call regular phone lines from anywhere in the world. And this is portable version of skype, packaged as a portable app this mean you can communicate on the go.

features:

Free Skype-to-Skype calls.
Call phones and mobiles, send SMS.
Free instant messaging.
Voicemail.
Free video call.
Forward calls to a phone when you’re offline.