Last news from iPhone tell us that you can now make streaming video from your iPhone over its Wifi to any Mac video application, including iChat, Photo Booth or Skype. It needs install some applications to can use the iPhone in these programs as Skype or iChat.
Video streaming from cellpohones is not much widespread today, but solutions like this and broadband connections may make this change sooner than later.
At the moment, we have to wait to 3G iPhone generation launch to see if it includes this application, or some other with the same functionality.
Here, you can see a video of this application.
Via Tuaw