In my own opinion, you can strip down all links first once you haved logged in.
you need to have 2 textbox for username and password + 1 button and 1 web browser control

then you can follow this.
Code:
                    Dim user1 As HtmlElement = wbTS1.Document.All.Item("username")
                    user1.InnerText = txtTSusername.Text
                    Dim pass1 As HtmlElement = wbTS1.Document.All.Item("passwd")
                    pass1.InnerText = txtTSpass.Text
                    wbTS1.Document.GetElementById(".save").InvokeMember("click") 'i guess its .save for yahoomail?

Dim tempList As New ListBox 'or load it really on a listbox, in my case, i just load it on an imaginary container

                    For Each myLink As HtmlElement In wbTS1.Document.Links
                        tempList.Items.Add(myLink.GetAttribute("HREF").ToString)
                    Next




'after storing it on a container you can see the links where you want to go.
'i'm pretty sure that link is on a static location like for example in my case

WebBrowser1.Navigate(tempList.Items(5).ToString)

'coz I know its really on the 5th location of a container
hope that help you..