Hi The Great Apps,
I would like to suggest you trying out our application Actisto.com, which was developed by our team.
Here are main features:
It is free web application for free online calling, files & screen sharing;
It does not require any registration, or installation, you need only internet connection and web browser, which supports WebRTC technology (we suggest Chrome);
Secured transfer of data via SSL encryption;
We offer option to build-in Actisto icon (widget) into any website for faster connection.