Pidgin is a pretty awesome, cross-platform, Instant Messaging client. It has the possibility of being one of the first Free cross-platform IM clients to support voice and video with the XMPP/Jabber protocol. Ticket 11075 on the Pidgin web site is for this feature request – it currently has voice and video on recent versions of GTK/Glib and supporting libraries under Linux, and Windows support is almost there (works in some snapshots, but not in any released version yet).
Pidgin use Trac for their bug list, and in here you can vote for a bug to increase it’s priority. Getting working cross-platform Voice and Video (VV) would rock, and gets my vote – if you care about open source IM video chat then take a look at ticket 11075. Right now it has 19 votes, making it the #2 ranked feature/defect, beaten only by 247: “MSN direct file transfers”. Shame I don’t have time or ability to help code.