Walking Outliner?

I need to know the hierarchy of my 3D objects in Blender, especially meshes, so that I can effectively export IPO animation. Is there a way to do this in Python? I see a “getParent()” function for Object, but no corresponding “getChildren()” function. I note this hierarchy is present in the Outliner, but I’m not sure how to get it out myself.

Does anyone know how I can walk the hierarchy tree, or figure out the parent/child relationship of the objects I export to a file?

Thanks for any feedback!