Skype has recently started charging $10/month for group video chat, which neither me nor my friends wish to pay. Are there any free, cross-platform (Windows and OS X) applications which can do video chat between 3 or more people at once? Either a desktop application or a web application would work. When making recommendations, it would be helpful to state whether it's a desktop or web app, what features it has, and whether it requires sign-up for the service. Thanks.
Google+ hangouts is the only free tool I've been able to use – it's a webapp though.