Get opened tab in IE

Question

I'm using the code below to open a new tab or a new window in IE:

        object m = Type.Missing;
        object url = "http://www.igoogle.com";
        InternetExplorer ie = new InternetExplorer();
        ie.Visible = true;
        object url2 = "http://stackoverflow.com";
        ie.Navigate2(ref url, ref m, ref m, ref m, ref m);
        ie.Navigate2(ref url2, 2048, ref m, ref m, ref m);

My question is how can i get an opened tab in the exemple above, i'm opening the url2 in a new tab (2048 flag).

I want to get the opened tab and i want to know wich tab is opened by code and wich one is opened by hand ( add new tab and write the url in the browser text box)