How to GetWindowText() of an application in another address space?

[Eq]

GetWindowText() only applies to child controls in the current process. Are there any methods that I can read the text of the child controls in another applications? Thanks all!

[Michael Dunn]

GetWindowText() works on any window. :)

[Eq]

How about other common controls like listcontrol, treecontrol? Can I access the tree control in windows explorer through my program? Thanks all!!