get the child of windows in c#

Hi, Suppose i have a list of all active applications in my system and every application is a window using GetWindow() from the API. I can get their handles, the tittle af the applications, get the All children of any window of this application .I mean.. if this window is open, I'd get the handel of Address bare(because we can regard it children), and access to the content that is " www.msn.com ". Now i want to Know how i can to do all this task by classes in C# your help is greatly appreciated.