A variety of software exists that allows one to setup a videoconference. It should be noted, however, that they do not all work with each other. Basically, there are three overarching categories: H.323, Instant Messenger (IM), and Internet Phone. Polycom's PVX and Ekiga use the H.323 protocol (and a user running the one can talk to the other). AOL Instant Messenger, iChat, Yahoo Instant Messenger, and Microsoft's Live Messenger use different protocols (though mercifully Yahoo can talk with Live Messenger, and AIM can communicate with iChat, Apple's Instant Messenger). The Internet Phone category is more geared toward voice communication (as one might suspect) rather than video, but many programs in this category can do videoconferencing, such as Skype.
Below is a diagram illustrating (to the best of the author's knowledge and experience) what software (or hardware, in the case of the VSX) will communicate with what:
If you are looking for a professional-quality videoconference (or the party you wish to communicate with is using professional equipment), then hardware-accelerated equipment like Polycom's VSX 7000e system or Polycom's ViaVideo (working with the PVX software) is the way to go. We would be more than happy to help you setup an event utilizing this equipment: just fill out this form.
On the other hand, if you need to communicate with a remote party on a regular basis and/or quality is not absolutely critical, using an Instant Messenger or Internet Phone program is a good plan. To assist you in this, we have provided tutorials for many common programs of this type, but you are welcome to contact us for technical support as well.
Below are links to the tutorials in question:
