Tox is an open source secure alternative to the likes of Skype. To install it, you need to install the core package and one of the available GUIs. You can compare some of the available clients here but personally I like qtox. The below will pull in the required dependencies.
sudo pacman -Sy qtox
If you want the latest Git version, you can install qtox-git from the AUR.
yaourt -S qtox-git
Make sure you run that as a regular user – not root. This pulls in the core package from the ABS repository also.
To add a contact, you will need their Tox ID – which looks like this:
56A1ADE4B65B86BCD51CC73E2CD4E542179F47959FE3E0E21B4B0ACDADE51855D34D34D37CB5
If that is a bit too annoying for you, you can use a free ToxDNS provider, such as utox.org. This will give you a “username@utox.org” address to give your people.