Con la ShellExecute.
codice:
Option Explicit
Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long


Sub Command1_Click()
  Dim nRet As Long
  ' Al posto di c:\locandine.pdf metti il nome del tuo pdf 
  nRet = ShellExecute(Me.hwnd, "Print", "c:\locandine.pdf", vbNullString, 0&, 2)
End Sub

ciao,