We can login with multiple user from same computer ...:D want to know how ..follow the step below..
(Yahoo messenger , G-talk)
1) Go to Start
2) Navigate to HKEY_CURRENT_USER-->Software-->Yahoo-->Pager-->Test
3)ON the Right side if the page , Right click and choose new Dword Value.
4) Rename it as " Plural ".
5)Double click and assign a decimal value of 1.
6) Now close registry and restar yahoo messenger and try Multiple Login