VSee, free for students and educational establishments, unites voice calls, video calls and screen- and file-sharing into one secure service. Unique to the program is its proprietary method for streaming video. VSee is light on bandwidth, and dynamically adjusts video quality when it senses network congestion. All traffic is protected using 256-bit AES encryption.
Even if you're not in the education world, you can still make group video calls for free to an unlimited number of users, as long as they install the client for Windows or Macs. The free account -- which lacks ads, by the way -- limits you to one screen-share per day. For $9 per month, you can do a show-and-tell with as many screens as you like; for $49 per month, all meeting participants can share screens. As of this writing, VSee's iPhone app is expected to roll out in a couple of weeks, with the Android version coming along later in the year. As you read this, the company is finalizing an update to its iPad app, which will enable it to receive screens.