Other acts billed to appear at the three-day festival include Sheryl Crow, Willie Nelson, Jewel, Alanis Morrisette and Metallica.

British acts including Fatboy Slim, Elvis Costello, the Chemical Brothers, Jamiroquai and Bush will also play at the event, held at the former Griffiths air force base near the town of Rome.

But fans looking for the spirit of '69 are likely to be let down - the festival is as much a corporate party as a celebration of music.

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Thirty years after Yasgur's Farm, Bethel, played host to the likes of Jimi Hendrix and Jefferson Airplane, flight and hotel packages are available to the event and they can be paid for on a Woodstock platinum credit card, along with the $180 (£113) cost of entrance.

In 1969 it cost $6 to enter for a day - although many of the 500,000 there climbed fences to get in. In 1999, even watching at home on pay-per-view TV or on the Internet will set fans back $60 (£37).

Meanwhile exclusivity contracts have also been sold to soft drink firms, ice cream sellers and condom manufacturers.

Drugs are strictly prohibited - but local traders report a booming trade in drug paraphernalia.

For many, the memories are not of the 1969 festival, but of the first Woodstock anniversary show in 1994, which original performer Neil Young dubbed "Greedstock".

But organisers are not phased by the corporate invasion of Woodstock, and praised the modern site.

'Billion dollar facility'

Michael Lang, who put together the 1969 show, told the New York Times: "The irony is terrific. It's almost like revenge - you get to use this billion dollar facility for a rock concert."

Lang is confident the spirit for 30 years ago will live on. He said: "My hope is that it is an experience very much like the other two were. The first two were magic.

"People feel comfortable and sort of let down their defences and open up to people and they become a community and relate to each other in a way that is, I think, different from any other time in their lives."

Traffic jams have been building up outside the site

Co-prodcuer John Scher said: "You put a few hundred kids in a field in upstate New York and certain things happen. The pure magic of that, quite honestly, was too irresistible not to try that one more time."

Also looking forward to the event is the town of Rome, which has been depressed since the B-52 base closed in 1993. It can expect a $30m boost to the local economy.

By Thursday 170,000 out of 250,000 tickets had been sold.

Guitar legend Jeff Beck was due to appear, but pulled out - as he did in 1969 - due to "scheduling problems".

Only one of the 40 musicians who performed in 1969 is back for the 1999 show - former Grateful Dead performer Mickey Hart will appear with his current group, Planet Drum.

Plans for a European Woodstock festival which would have been held last weekend at Wiener-Neustadt, Austria, were postponed after Michael Lang said "more time" was needed to prepare for "a safe and successful event". He hopes to re-arrange it for the summer of 2000 or 2001.