Get the steak home from the butcher and unwrap it. Depending on it's size, you may want to cut it into 2 or 3 pieces (take a look at your grill to judge).
Put it in the Ziploc bag. Make sure it is a Ziploc - anything else will result in utter failure.
Add the salad dressing, seal the bag (preferably removing most of the extra air first) and mix it all around.
Stick it in the 'fridge for at least 24 hours. Visit occasionally and massage it to rub in the Paul Newman.
After a day or so, get a good fire going in your grill. It should be hot but not too hot, if you know what I mean. (If you have a gas grill, well, that's just too bad).
Open the wine. Pour a glass. Mmmmm, isn't that good? Let it breathe for a few minutes while you finish getting the grill ready.
Throw the steak on the fire - over the hottest part so you sear it. Turn after one minute. *Caution* - Newman's Italian dressing is flammible - use caution when you open the lid to flip the steak.
Flip it and let it sear over the hottest part of the fire for about one minute.
After a minute or so, flip again, move to a slightly cooler part (but not too cool). Put the cover back on.
Now's a good time to revisit that glass of wine.
After a couple minutes, flip the steak again - again, place it over a medium-hot part of the grill. Cover on, leave it for about a minute. Quick sip.
Remove the steak from the grill and place it on a cutting board. LET IT SIT for about 3 to 5 minutes for the juices to redistribute. Have a little more wine.
Using a sharp kitchen knife, slice thinly, at an angle, against the grain of the meat.
Serve with, well, it really doesn't matter - this stuff is so good it goes with anything.