From what I've seen, the N800 (OS2007/RTCOMM) seems to use jingle-video over Jabber/XMPP for video confrencing. It's not unique to the gTalk service, that's just one of the more popular Jabber/XMPP based servers people use. I can (for example) get a N800 to N800 video confrence going via my own private Jabber server.

The problem is that (suprisingly) the N800/OS2007 seems to be the only Jabber/XMPP client on the planet to have jingle-video support. Even Google's own gTalk PC client doesn't even have it, and they basically authored the jingle-audio, jingle-video specs! I guess if you look at it, Nokia is just way ahead of the curve, not that it helps.

Anyways, I *think* that as soon as there are PC Jabber clients that support jingle-video we'll have some real options. Why gTalk isn't there already is a mystery, but they did buy a video-centric company pretty recently. Other Jabber clients like PSI and Coccinella have threads indicating they are looking at video also.

Now, from what I've read, OS2008 has promised two things:

1) Support for video over SIP via h.263 (normal, not h.263+) per Arki Jaaksi's blog.
2) "Video calling between two devices or to any compatible PC " from the "Communication Features" on http://europe.nokia.com/A4579471

Thus, there seem to be more video to PC options coming with OS2008. Maybe Nokia has a jingle-video Jabber client coming, or know of one? If someone has an N810 or OS2008 and wanted to place a SIP call to me I can verify that h.263 works to the PC though.