Update!! Now Yahoo Messenger 10 is Ready to be used with Windows 7! Absolutely Works well!
Officially, Yahoo hasn’t developed the Yahoo Messenger Client that supports Windows 7. The question is: how we can chat with our Windows 7 if there is no chat client that supports with it. Yes, until right now the third party chat client of Yahoo Messenger for Windows 7 hasn’t launch either. The answer for this question is simple: Try to use Web Messenger Chat Client.
Yes, just pointed you browser on Windows 7 (Internet Explorer) to one of the Multi Protocol Web Messenger, such as www.meebo.com or the official web messenger of yahoo messenger at webmessenger.yahoo.com and the you can start using you yahoo account and make a chat in ther.
Lack of this tricks
As long as we understand, web messenger did not has any chat room that related to Yahoo Messenger, and also the web webcam service. This means the chat room or webcah sharing is only available for the web messenger users only.