Google Talk Multiple Instances

Google Talk: Run Multiple Instances or Login as Multiple Users
Run google talk with the following switch: /nomutex

If you installed google talk to the default location, you can easily create a shortcut to this setting.
1. Right-click on the desktop
2. Select New
3. Select Shortcut
4. Paste this into the text box:"c:\program files\google\google talk\googletalk.exe" /nomutex