I'm looking for a free Skype alternative that supports group video calls and is cross platform (Windows, OSX, Linux). Any ideas?
There is a service called oovoo http://www.oovoo.com thats supposed to support up to 12 people and is free
if you have the resources you could also try setting up a webbased application on a server such as Big Blue Button. its flash based and you host all your webconference youreself so security isnt an issue
These days Google Plus Hangouts work really great, I ended up using that :)
It's a service integrated with Google+ called Hangouts. It allows you to set up meetings with several people with the option of sharing webcams. Whereas most of these services cost money (such as Skype premium), Google+ Hangouts is completely free :)