In October 1994, three student filmmakers disappeared in the woods near Burkittsville, Maryland while shooting a documentary.
A few days later, they were found by a search party after they called for help.
Superman
Who ever speaks to this guy has got the most important interview since God talked to Moses.
(Clark’s cell phone goes off, playing the Superman theme)
Hey wait! YOU’RE SUPERMAN!
Casablanca: Victor and Ilsa get the letters of transit via smartphone through online broker lettersoftransit.com. Rick consoles himself by Facebooking the sexy .jpgs of Ilsa he took in Paris.
Night of the Living Dead could easily play more or less the same way if set in 2012 as it did in 1968 (or 1990). Barbra & Johnny are driving out to rural PA to visit their father’s grave. They listed to their iPods instead of the radio and they’ve both turned their cellphones off to avoid nagging phone calls from their mother. They get attacked at the cemetary; Barbra drops her purse running back to the car. When she get’s to the farmhouse the landline doesn’t work cause a pole went down. Sure everyone else has cellphones, but they doesn’t work 'cause the farmhouse is in a deadzone (or the tower’s down). Only the last part would need any dialoge or a new scene to explain.
Bruce Willis’ limo driver is on a car phone during the heist, missing action going on directly behind him because he’s having too much fun.
Commando
Sully sees Matrix in the Mall and calls El Presidente to tell him he’s not on the plane
Quest for Fire: “Hey, Og, could you loan us a pot full of embers? Thanks, dude…”
Stagecoach.
“I’m callling ahead to confirm that the cavalry will be available when we arrive at Dry Fork. No? Okay, we’ll stay put until you call us back. Thanks.”
The Seventh Seal - Antonius Block downloads a strong chess-playing app and checkmates Death.
Wasn’t this lampshaded in the first Harold and Kumar movie? IIRC they get halfway down their hallway, realize that they’ve left their phones and decide it’s too far to walk back to get them. Hilarity ensues.
It’s not in the Thread intention, but the infamous Death issue of National Lampoon had a one-page ad for the book Bobby Fisher Teaches You How to Beat Death at Chess.
“The Man Who Knew Too Much” – Jimmy Stewart, Doris Day
The pivotal moment is when Doris Day sings Qué Será Será really loudly from the theater stage, and kidnapped son Hank reunites with her by following her voice.
It just wouldn’t have been the same if she’d called and said, Hank, where are you? Get down to the theater right this minute!
Romeo and Juliet:
dont worry fr lawrence says ill wake up in six hrs and then we can go. xoxox
Star Wars:
Luke: Hey, Ben! Got some droids here, say they’re yours.
Ben: I don’t remember owning any droids.
Luke: Okay, never mind then.
There is just such a car phone in Die Hard, in the limo that Argyle’s driving. They show him using it in several scenes, and clearly mean it to be an unusual thing that Argyle’s using for its novelty value while everything is happening in the building above him.
The contemporaneous (1988) movie Miracle Mile has a single character with a mobile phone; when she pulls it out in the 24-hour diner, it’s a device to show that she’s a very, very important person with access to people and information that a common person could never have, and the other diner patrons are appropriately impressed.
Well, it would have been useful if it hadn’t been dropped in the river along with the map… 
My contribution: Run Lola Run
Sequence one: the robbery probably wouldn’t have occurred; she’d have been able to tell him she was coming, and they could run away.
Sequence two: probably much the same as the original.
Sequence three: she’d never have gone to the casino, since she’d know he recovered the money.
Or, more likely, for all sequences, she’d stop running every few seconds to text Manni, and he’d get busted by Ronnie.
And only notice it when it’s really important. Yeah. If the above plots happened in real life I don’t think a cellphone would be the deus ex machina it’s being made out to be.
Here’s a 1988 commercial for “portable” cell phones. Not something you’d slip in your pocket.
I think I’ve spotted a flaw in his marketing strategy.
This was my thought. Most cell phones of the mid-to-late 80s would have been brick phones, which one did not carry about as casually as today.
Spartacus. Having to distinguish among all those guys standing in front of him, the Roman commander would have just called Spartacus’ cell. Then it’s a simple matter to arrest the man whose tunic is chirping, “deedle deedle deedle.”
The Ten Commandments. “Aaron, I’m on my way back down the mountain. The Lord faxed me some commandments. How are things in camp? What? You’re building a what now?”
Star Trek V. “What does God need with a cell phone?”
Pulp Fiction. “Five long years, he wore this phone up his a–. Then when he died of dysentery, he gave me the phone. I hid this uncomfortable piece of metal up my a-- for two years. Then, after seven years, I was sent home to my family. And now, little man, I give the phone to you.”
IIRC, in Six Degrees of Separation (1993), there’s a long shot of a businessman character conversing on his cell phone as he walks through the airport. When he walks through the metal detector, he hands the phone to the security guard without hanging up, then takes it back on the other side and resumes the conversation. At the time, it was meant to seem nearly as impressive as the second Terminator dissolving through the barred hospital door.