With C2Call you can make web P2p voip calls straight from your browser.  it works on almost every OS including Linux, Windows and even the Mac.  Basically it’s a widget that gets loaded temporarily from the C2Call web page and into your browser.

The best part about this is that you don’t have to install any software to make a direct P2P voip call. All you have to do is send a call invitation through email (or through a direct link).  The recipient just clicks the link and is taken directly to the call page where you will be a directly connected.

Currently C2Call is still in beta, but that doesn’t prevent you from signing up.  Sign up here.