i usually let them know the atis i have when calling for clearance and taxi. i do it for clearance since at the end they usually say "current ATIS is Tango," or something to that effect, so it save them the extra words. that and i think when you send a PDC you have to imput the current atis code. not sure on that, since we don't have it yet (heck, just got ACARS W&B thursday)