Please help me sort out all the various text/voice/video messaging options that are available on the tablets now.

Under the heading of Communication on OS2008 I now have "Internet call", "Chat", and I just installed "Gizmo". I have also heard of "Pidgin" and I know that "Skype" is coming soon (already available in OS2007).

Thanks to zerojays post here, I know that I don't necessarily need Pidgin because I already have something that does "Jabber"... that must be the "Chat" application, right?

So can someone briefly summarize what all of this means? Which of these does the following: text chat; voice calls; video calls? And what would someone need on the other end (assuming not a Tablet) to communicate with me? Feel free to mention the protocols (SIP etc) that each supports if that helps to clarify things.

Thanks!