ModuleID is just like PortalID.  It's a Public ReadOnly Property and you get it for free in your codebehind.  Just call ModuleID.  I don't think you can reference it directly in your stored procedure.  You'll want to use the DAL or DAL+ to send it to your stored proc.  Try something like:

        Private Sub cmdUpdate_Click(ByVal sender As Object, ByVal e As EventArgs) Handles cmdUpdate.Click
            Try
                Dim ctlMyData As New myDataController

                Dim objmMData As myInfo = New myDataInfo

                objmyData.ModuleId = ModuleId
                objmyData.ItemId = ItemId
                objmyData.PortalID = PortalID
                objmyData.UserID = UserInfo.UserID

                If Common.Utilities.Null.IsNull(ItemId) Then
                    ' add the content within the MyData table
                    objMyData.AddMyData(objMyData)
                Else
                    ' update the content within the IDPBuilder table
                    objMyData.UpdateMyData(objMyData)
                End If

                ' Redirect back to the portal home page
                Response.Redirect(NavigateURL(), True)
            Catch exc As Exception    'Module failed to load
                ProcessModuleLoadException(Me, exc)
            End Try
        End Sub

You should be able to find step by step instructions pretty close to this in the tutorials at the top of this forum.