You've got to give Yahoo! some credit for really pushing the Vista stuff here:

This week, our Yahoo! Messenger for Vista team is at the Microsoft MIX conference in Las Vegas (March 5-7). The MIX conference is a chance for developers utilizing Microsoft platforms to discuss new ideas and technologies, as well as share what they’ve created.

Great work is continuing on Yahoo! Messenger for Vista, and members of the team will be meeting with reporters and technologists at MIX to give them a preview of what’s coming up in the next Beta release. We wanted to make sure our readers and users got a sneak peek as well.

The key feature in the next Beta release will be voice, allowing users to make free PC-to-PC calls and low-cost PC-to-Phone calls right from their PC. And if you have a Phone In number, you will also be able to receive calls from your friends in Yahoo! Messenger for Vista.

As part of the voice feature, our designers have been working on some cool voice visualizations for the product that leverage the WPF 3D integration. So even if you’re not having a very interesting phone conversation, we guarantee you’ll be mesmerized by the awesome effects.

While we don’t have a definitive release date for this next Beta version of Yahoo! Messenger for Vista, we’ll keep you posted here on the blog. In the meantime, if you are running Windows Vista, please download and try out the preview version available at http://messenger.yahoo.com/vista.

Looking good. I'm not a Yahoo! Messenger user, but I wish Microsoft's IM app looked this good in Vista.