Ashok,
It is possible,but you should use SharePoint webservices to do that. Here goes a list of webservices (I'm not exactly wich one you should use - I think is "UserGroup.asmx" - take a look on it's methods).
http://msdn.microsoft.com/en-us/library/dd878586%28v=office.12%29.aspx
Hope this helps..
João Selarim