Currently, the VTech usb7200 is the only USB phone that's been verified and certified by Yahoo! for use with Messenger. This phone is approved for use in North America only.
There may be additional USB phones that work with Yahoo! Messenger. They are not recommended, however, since they haven't been verified or certified by Yahoo! for use with Messenger. Stay tuned as we bring more USB phones into Yahoo!-certified operation.
Where's the Contact Customer Care button? With so many improvements to Messenger since the version you're using (lots more features and reliability), we figured you're ready to move up. So get your upgrade and with the new version, rest assured if you have questions, you’ll find that friendly button on its help pages.