Laurie wants to conduct an online bible study with small audiences of up to 10 people. Leo says that Google Hangouts tops out at eight people, so that's pretty good. It also switches between active speakers automatically, and it's free.
GotoWebinar.com is designed for hundreds of people. It's a bit more sophisticated, but it's not free. It's about $89 a month. WebRTC is a new browser protocol that is the easiest way for those Laurie wants to invite. Jitsi is another solution with multi party video conferencing. They offer no technical limit, and there is a free version.
(Disclaimer: Citrix is a sponsor)