But closer inspection reveals those hip kids are, in fact, a hooded Iraqi prisoner awaiting execution, an insurgent fighter lobbing a hand grenade and a soldier bearing a shoulder-mounted rocket launcher.

Gone are the trademark white earphones, replaced by electrocution cables tied to the prisoner’s wrists - a wry subversion echoing the scandal in which US soldiers are alleged to have tortured Iraqi civilians.

Fusing two of pop culture’s most talked-about topics, iPod and Iraq, the “subvertisements” mysteriously appeared overnight on American streets last week, as anti-war artists hijacked Apple’s award-winning ad campaign for political purposes.

But imitation may be the lowest form of flattery for the fashionable computer company, which closely guards its brand. The logo for iPod, two million of which have been sold worldwide, is cleverly replaced by “iRaq” and the marketing slogan “10,000 songs in your pocket” disappears for “10,000 volts in your pocket, guilty or innocent”. Apple’s infamous logo is morphed into a hand grenade, in a move likely to incense company CEO Steve Jobs, who announced the European launch of iTunes Music Store in London two weeks ago.

The poster parodies first surfaced on subways and streets in New York’s SoHo this month, often sneakily slipped into legitimate hoardings of official iPod ads for maximum effect.

Last week, they were flyposted on billboards along Hollywood’s top celebrity spot, Sunset Boulevard, and they are expected to appear in cities around the world in coming weeks, now that designers have placed them online, where sympathisers are encouraged to download and print off their own pop propaganda.

“It’s about re-taking the field of political discourse, six square feet at a time,” said the designer behind the activist art, who wanted to remain anonymous and is one of a growing number of “culture jammers”.

“It is about freedom; a freedom more real and comprehensive than the freedom being sold in the iPod campaign, [which is] the freedom to be completely isolated in your own private party for little more than 200 bucks.”

“The iRaq poster is a sign of a freedom far more genuine than the freedom the American military is supposedly granting to the Iraqi people, through what is perhaps the most misguided and unratified
military invasion in recent history.

“It’s about refusing to let the sluts in the military-industrial complex and the sluts in the halls of advertising power set the terms of debate for a world of people whose opinions are more diverse than any political slogan or cookie-cutter image can express.”

The adverts, which also run across TV and magazines, were recently named America’s ad campaign of the year and are now being expanded in the UK for the launch of iTunes on this side of the pond.

A spokesman for TBWA\Chiat\Day, the marketing company which conceived the campaign, said he was aware of the posters but, like Steve Jobs’ Apple, refused to comment further.