Communication And Messaging/Video
freeware
Gizmo
Gizmo uses your Internet connection (broadband or dial-up) to make calls to other computers. With the click of a mouse, you're connected to friends, family, and colleagues anywhere on earth. It's just that simple. You talk clearly for as long as you want for free.
With inexpensive add-ons like Call In and Call Out, you can talk to any telephone, mobile or landline on the planet.
freeware
Loudtalks
Loudtalks brings voice back to the Internet communications. It's a little application, which allows you to talk to your friends or colleagues instantly with a single touch of a button. Think walkie talkie. It's faster than text chat and more convenient than calls. It supports one to one and one to many communication. Incoming messages could be re-played. The application is fast and lightweight and doesn't require any configuration.
adware
ooVoo
ooVoo is a multi-user video chat application which supports up to 6 users simultaneously. You can also send and receive video messages and files to other ooVoo users and even send video messages to users who don't have the software installed.
open source
Mumble
Mumble was made to improve voice communication in games. This program features shorter delay and better implementation of Speex than most other free clients. Plug-in support for postional audio in games has been implemented, and it comes with a plug-in for Battlefield 2. Installer includes the client Mumble and the server Murmur.