Is there any client other than the web interface for Google video chat?
You can try Jitsi ( https://jitsi.org/ ). It supports gtalk audio (not video) chat on windows, but it is EXTREMELY resource hungry; it uses 200-300mb of RAM. Complete deal breaker for me.
I think the only thing we can do is wait patiently for someone to implement video support for the windows version of Pidgin. It can be done: http://developer.pidgin.im/wiki/Using%20Pidgin#WhenwillvoiceandvideobeimplementedonWindows
According to Wikipedia, there are no other clients capable of google xmpp video chat in Windows: http://en.wikipedia.org/wiki/Comparison_of_instant_messaging_clients#XMPP-related_features
(btw, iCall doesn’t support google video, I tried; only works on their iCall xmpp accounts, not google xmpp)
The thing is, all the chat clients for Windows which support google xmpp need the Jingle Protocol, which is implemented in linux but on windows it’s still very elusive: http://en.wikipedia.org/wiki/Jingle_(protocol)
It seems though that a decent google voice plugin for Miranda might come out soon: http://forums.miranda-im.org/showthread.php?13768-Jingle-Jabber-plugin-(JGTalk-Protocol-JGmail-libjingle-mod) (voice calls should work, but at this time, video calls are still not finished).
If this is at all an option for you, you can get rid of google talk (and XMPP) altogether, and use SIP with Linphone ( http://www.linphone.org/ ). Linphone is open source and supports efficient and snoop-free videochat across all platforms. There’s an android app (as well as iOS and blackberry) and of course windows and linux versions.
You would need to register a Linphone SIP account (or any SIP account anywhere else works), and you’d also need to get your friends to use SIP instead of google xmpp.
This is what I’m currently going for anyway; thought I’d let you know.
There is a modification for Skype that allows G-mail and Google chat and Google voice. i think Trillian has Google video chat as well.
I found this software, the link goes to softonic (I do not recommend to download anything there), but maybe you find this software somewhere else, too.