Users of Skype and most of the popular instant messaging programs should soon all be able to talk to each thanks to new software coming soon from Santa Cruz Networks.

A new plug-in from Santa Cruz lets Skype and Google Talk customers make voice and video calls to each other, the company said.

Early next year, Festoon Unity, the new feature added to Santa Cruz's Festoon application, will also support AIM, Yahoo! Messenger and MSN Messenger, so that users of those services, and those of Skype Technologies and Google, can all make voice and video calls to each other.

Festoon, which users can download for free, currently enables customers of the Skype and Google Talk voice-over-IP services to make video calls, but only to other users on the same platform. The new release supports voice and video calls from one service to another, initially between Skype and Google Talk and later among users of the various platforms.

Separately Skype released a beta of Skype 2.0 that supports video calling with other Skype users.

Festoon also lets users make group voice and video calls comprising as many as 200 participants. Future upgrades will include downloads of video effects and wallpapers, Santa Cruz said.

Since the first IM (instant messaging) services appeared, built on proprietary platforms, users and some providers have called for interoperability. While some IM services have formed interoperability partnerships with others, the platforms aren't open and compatible with all.

But the launch of Google Talk in August spurred renewed discussion of IM interoperability because Google built the application using an open protocol and said at the time that it was committed to working with other IM service providers to enable interoperability.