Call Yahoo , Windows Messenger From Google Talk

Yahoo! Messenger and MSN (Windows Live) Messenger users can chat with each other easily without changing clients. Similarly, Google is working with AOL to allow users of Google Talk connect with their AIM buddies. (Skype?)
Now consider a completely different scenario - how do Google Talk users talk to their friends who are using Windows Live or Yahoo! Messenger ?

Here’s a a possible solution to make voice-over IP calls between Google Talk, MSN/Live Messenger and Yahoo! Messenger for free.
1. If you are on Google Talk and want to voice chat with someone on Yahoo!, add service@gtalk2voip.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it as your Gtalk friend and then send the following message to your new buddy:
CALL xyz@yahoo.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it [use your friends Yahoo! ID instead of xyz]
2. If you are on Yahoo! Messenger and want to connect with a Google Talk user, add gtalk2voip@yahoo.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it to your Yahoo! buddy list and send the following message:
CALL xyz@gmail.comThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it [use your friends Google Talk ID instead of xyz]
For more details visit GTalk2VoIP and their blog. Thanks Nash and Ash.
There are rumors that a new version of Windows Live Version is in the works that will connect to Google Talk and AOL Messenger but this is likely to support only text chat, not voice calls.