Here are the ways that may help you use the messengers to login in more than one account.
For Gtalk :
1. Create a shortcut for the Gtalk in the desktop and an extra arugument “/nomutex” in the ‘Target’ text box.
2. Now use the shortcut and run multiple instances of Gtalk as you like.
For Skype :
1. You can do this in two ways for Skype. Create a shortcut for the skype in the desktop and add an extra argument “/secondary” in the ”Target’ , save the shortcut and run instances.
2. Skype can run an instance for every individual users. So create two or more users and use the following commmand from the shell to run instances. ‘ runas /user:XXX “C:Program FilesSkypeSkype.exe” ‘, where XXX is the username in your pc.
3. The above said way can also be done by right-clicking the shortcut and selecting the “Run As” command from the context menu.
For Yahoo :
1. Open the regedit ( Start -> Run -> regedit ), traverse to “HKEY_CURRENT_USERSoftwareyahoopagerTest”.
2. Create a DWORD registry value named “Plural” by right clicking the right hand side window.
3. Double click the new DWORD entry and set the value to 1.
Thats it. Run multiple instances of your favourite messengers and have fun. 😉