Ok here is my code from my MasterPage so far:

VB Code:
  1. Partial Class Header
  2.     Inherits System.Web.UI.MasterPage
  3.  
  4.     Private mLanguage As String
  5.     Private mDirective As String
  6.  
  7.     Public Property Directive() As String
  8.         Get
  9.             Return mDirective
  10.         End Get
  11.         Set(ByVal value As String)
  12.             mDirective = value
  13.         End Set
  14.     End Property
  15.  
  16.     Protected Sub Page_Init(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Init
  17.         Select Case Me.Directive
  18.             Case "Products"
  19.                 Products.ImageUrl = "images/new_header/Menu_Items/Products_On.jpg"
  20.             Case "About"
  21.                 About.ImageUrl = "images/new_header/Menu_Items/AboutUs_On.jpg"
  22.             Case "Search"
  23.                 Search.ImageUrl = "images/new_header/Menu_Items/Search_On.jpg"
  24.             Case "Employment"
  25.                 Employment.ImageUrl = "images/new_header/Menu_Items/Employment_On.jpg"
  26.             Case "Contact"
  27.                 Contact.ImageUrl = "images/new_header/Menu_Items/Contact_On.jpg"
  28.         End Select
  29.  
  30.     End Sub
  31. End Class

When my contentpage PreInit event fires, I would like it to change the Directive property of the MasterPage, but I'm not sure how to expose it from the contentpage.