I couldn't find any easy way to traverse the entire asp .net control tree using the framework classes, so I decided to write my own implementation.  In the end, I wanted to be able to traverse all of the controls and get all which are of a certain type.  First, the method which traverses the tree:

public static void RecurseControls(ControlCollection controls, FindControlDelegate callback)
{
    foreach (Control c in controls)
    {
        callback(c);
        if (c.Controls.Count > 0)
        {
            RecurseControls(c.Controls, callback);
        }
    }
}

This basically recurses through the control tree and calls a given delegate for each control found.  Here is the delegate:

public delegate void FindControlDelegate(Control control);

To top it all off, here is the method I wrote to find all of the controls of a given type on a page:

public static List<T> FindAllControls<T>(Page page)
    where T : Control
{
    List<T> controls = new List<T>();
    RecurseControls(page.Controls, delegate(Control c)
    {
        if(c is T)
            controls.Add(c as T);
    });
    return controls;
}

I am usually not one to use cryptic programming techniques such as inline delegates, but in this case it just made sense.  Otherwise, I would have had to somehow share the object containing the list of found controls between two different methods.