If your Labor Day plans include taking in one last summer blockbuster at the local multiplex, take this advice: leave that cell phone in your pocket.

Forever on the prowl for the next big thing in movie piracy, the motion picture industry is zeroing in on small and increasingly-powerful mobile-phone cameras that might be trained on theater screens. Picture and sound quality lag behind their camcorder big brothers, but the devices offer something a camcorder cannot: stealth.

"It's a lot less conspicuous than somebody trying to bring in a camcorder," said Chris Null, editor and publisher of Filmcritic.com. "This is definitely a trend. Everybody has their cell phone at a movie."

The world saw the cell phone's imaging power with last year's clandestine taping of Saddam Hussein's hanging. Advancements in cell phone battery life and memory has now caught the attention of pirates and Hollywood.

The Warner Bros. Pictures invitation to screen the latest Harry Potter flick for reviewers underscored the motion picture industry's concern that the cell phone is the latest bootlegging tool.

"Please note that mobile phones and other handheld devices will not be permitted in the theater for any pre-release screenings of Harry Potter and the Order of Phoenix," the July invitation read. "Please leave such devices in the car."

A small number of hijacked movie cell-phone recordings are beginning to appear on BitTorrent sites. This month, a 21-year-old Australian man was arrested for allegedly uploading a copy of The Simpsons Movie he recorded with a cell phone in a Sydney suburb. The Australian Federation of Copyright Theft said police responded to four incidents of cell phone recording this summer.

"Generally, as technology gets better, people are using more than camcorders," said Elizabeth Kaltman, a Motion Picture Association of America spokeswoman. "They are using cell phones to capture movies. We're being more vigilant about them."

Hollywood is also watching for digital cameras capable of taking video. Last week a Virginia teenager pleaded guilty to a misdemeanor charge of unlawfully filming a motion picture after being nabbed capturing 20 seconds of Transformers with a Canon Powershot camera. She'd recorded the brief action scene to show her little brother later.

But cell phones, with their tiny sizes, ease of concealment and long battery life, are slowly becoming a headache for the entertainment industry.

"I'm seeing more reports about people taking out their cell phones at the movies," said Patrick Corcoran, a spokesman for the National Association of Theater Owners.

Despite the industry's growing alarm, the poor quality of cell phone recordings make them unpopular among downloaders – rating a distant fourth behind ripped DVDs, films recorded with professional-grade video cameras and movies pirated with handheld camcorders.

Consider the comments posted by discerning downloaders after a Simpsons cell phone bootleg appeared July 27th on the Pirate Bay site

"That was the worst copy I have ever seen," one pirate wrote. "I hate you and wish death on you. Why not take a long walk off a short pier you complete smack tard? You are a pathetic excuse for a human being. I hope you suffer when it comes your time you vile piece of scum. Have a nice day."

"WTF. Why even tape this shit?" another chimed in. "This copy sucks really hard because it's cammed with a cell phone camera," a third downloader whined.

A review of the pirated footage shows it's dark and grainy, with the screen floating around in the video frame. The sound is poor and out-of-synch, and frequently interrupted by the bootlegger's guffaws as he enjoyed the film he was pirating.

The impromptu laugh track didn't go unnoticed by another Pirate Bay user, whose post noted that the recording was "made worse by butthead laughing at every stupid joke."

The downloader's advice to future cell phone pirates: "Try not to make your laugh overpower what you are recording."