Try below code..
Public Class frm1
Public dtSongs As DataTable
'the datatable is filled in the form somewhere
Public Sub OpenForm3
Dim frmTemp As New frm3(Me)
frmTemp.Show()
End Sub
End Class
'Form 3
Public Class frm3
Dim myInstanceOffrm1 As frm1
Public Sub New(ByVal Passfrm1 As frm1)
myInstanceOffrm1 = Passfrm1
End Sub
Public Sub GetForm1DataTable()
'Access the DataTable
myInstanceOffrm1.dtSongs
End Sub
End Class