I've only had limited experience with webinars and I'm not certain these actually qualify as a webinar but Google+ offer what are called Hangouts. I have participated in a few of those and they seem to work quite well. Best of all *free* to all participants.
Oh, and if you sign up or have a Google+ account look me up and add me to your circles.
Start with some of our most frequented solutions or visit the Installation and Licensing Forum to get help installing your software.