Here is the VB.NET code
Code:
Imports System.Runtime.InteropServices
Module CueBannerText
    <DllImport("user32.dll", CharSet:=CharSet.Auto)> _
    Private Function SendMessage(ByVal hWnd As IntPtr, ByVal msg As Integer, ByVal wParam As Integer, <MarshalAs(UnmanagedType.LPWStr)> ByVal lParam As String) As Int32
    End Function
    Private Declare Function FindWindowEx Lib "user32" Alias "FindWindowExA" (ByVal hWnd1 As IntPtr, ByVal hWnd2 As IntPtr, ByVal lpsz1 As String, ByVal lpsz2 As String) As IntPtr
    Private Const EM_SETCUEBANNER As Integer = &H1501

    Public Sub SetCueText(ByVal control As Control, ByVal text As String)
        If TypeOf control Is ComboBox Then
            Dim Edit_hWnd As IntPtr = FindWindowEx(control.Handle, IntPtr.Zero, "Edit", Nothing)
            If Not Edit_hWnd = IntPtr.Zero Then
                SendMessage(Edit_hWnd, EM_SETCUEBANNER, 0, text)
            End If
        ElseIf TypeOf control Is TextBox Then
            SendMessage(control.Handle, EM_SETCUEBANNER, 0, text)
        End If
    End Sub

End Module
Usage
SetCueText(TextBox1, "Enter Name here")