Nice code, but why not use the AnimateWindow API?

Code:
    Public Declare Auto Function AnimateWindow Lib "user32" (ByVal hwnd As IntPtr, ByVal time As Integer, ByVal flags As Integer) As Boolean

    Public Enum AnimateStyles
        Slide = 262144
        Activate = 131072
        Blend = 524288
        Hide = 65536
        Center = 16
        HOR_Positive = 1
        HOR_Negative = 2
        VER_Positive = 4
        VER_Negative = 8
    End Enum
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        AnimateWindow(Me.Handle, 1000, AnimateStyles.HOR_Negative Or AnimateStyles.Blend)
    End Sub