OnePgr!

Join.me is a quick, remote controlling / screen & file sharing program from the makers of LogMeIn.

With ooVoo you can make free, high-quality video calls, voice calls, and send text messages to easily connect with your friends and family. Make clear and crisp video calls with up to 12 people at a time, on any device. Try it now!

Ekiga (formely known as GnomeMeeting) is an open source VoIP and video conferencing application for GNOME. Ekiga uses both the H.323 and SIP protocols. It supports many audio and video codecs, and is interoperable with other SIP compliant software and also with Microsoft NetMeeting.

A fully fledged, free email server solution, an open source project (GPL v2).

BigBlueButton enables universities and colleges to deliver a high-quality learning experience to remote students.

ÜberConference is the easiest and best way to make conference calls. Simply choose contacts from your address book and your conference will be created instantly. Participants don't even need to call in, as they will be dialed and/or sent an email invite to join.

Reliable, easy, effective web conferencing and online meetings.

Openmeetings provides video conferencing, instant messaging, white board, collaborative document editing and other groupware tools using API functions of the Red5 Streaming Server for Remoting and Streaming.

Voxeet has created a new generation sound technology that makes audio conferencing for distributed groups as natural as face-to-face communications. Voxeet offers affordable, crystal clear business quality conferencing services with one touch click-to-mobile.

Webex: The leader in online meetings, desktop sharing, web conferencing, video conference, net meeting, web conference. Get a free 14-day trial of WebEx online meetings, the leading web conferencing and video conference solution for sales presentations, webinars, online training, remote support.

Mark up websites, graphics, and photos, or start brainstorming on a blank canvas. Browse the web with your friends or make that conference call more productive than ever. No plug-ins, downloads, or firewall voodoo - its all here, ready to go when you are. Browser-agnostic, user-friendly.

Jump into a video chat with your friends without the need for creating accounts. Chat using just a WebRTC supported browser or phone.

Extremely low bandwidth video collaboration software that supports application sharing, desktop sharing, file sharing, and PTZ camera control. Also, this client is free without support for commercial, personal, and government use.