A 24-hour museum which gives internet users wide-ranging information about museums, galleries and heritage attractions has been given a celebrity send-off.

Broadcaster and food critic Loyd Grossman helped relaunch the popular web site which was set up in Brighton.

Another visitor was the broadcaster and writer Bamber Gascoigne.

Described as "the first national virtual museum", the site is home to a daily news and features magazine and attracts 5,000 visitors a day.

It has been nominated as one of the top 50 great British web sites.

Earlier this year, it became an independent registered charity.

Production of the site moved to offices in Market Street in the centre of Brighton.

Set up two years ago by the Campaign for Museums, it has three staff and is funded through Resource, formerly the Museums' and Galleries' Commission.

Mr Grossman, chairman of the trustees of the 24-hour museum, said: "We are here because there is a huge talent base in Brighton. It is said that there are more people in new media in Brighton per head of population than in Los Angeles.

"The site itself is really just emerging from its infancy, But we are already winning lots of awards from the national media and it is helping museums and galleries reach more people than ever."

Brighton-based broadcaster and journmalist Simon Fanshawe, said: "We are known for culture, and we are known for new media and we are very pleased to welcome the 24 Hour Museum to the city."

Unveiled at the launch in the Royal Pavilion was a link with Royal Mail which co-incides with four new stamp issues. This first web project has been designed by Brighton-based Victoria Baker.

The stamp issues are fabulous hats, celebrating the work of Britain's top milliners, released on June 18; pondlife (July 10); Punch and Judy (September 4); and Nobel prizewinners (October 2).

Jane Finnis, the museum development director, said: "We have managed to get a bit of a scoop. The site will give you a sneak preview of the new stamps a month before they go on sale."

Avid stamp collectors can write off or email for wallcharts on which to stick the stamps, try out stamp jigsaw puzzles and enter competitions with stamps as prizes.

The trail covers four museums or galleries where young visitors can explore displays relating to the four subjects.

Helen Wade, project co-ordinator at the museum, said: "Even if you can't visit all the museums, there are plenty of history pages on the sites where you can find out more.

"It's meant to be an interactive and visually-stimulating feast for young web surfers. Keep checking the site - we'll be launching more trails like this in the next few weeks."

Other museums already on the trails include the Science Musueum in London, the Museum of Childhood Memories in Anglesey, the Springhill Costume Musueum in Northern Ireland and the National Gallery of Scotland in Edinburgh.

The site has pages in the Welsh language developed by the Council of Museums in Wales and funded by the National Assembly for Wales.

Two further trails, designed and written by students on the creative media course at Lighthouse, the digital arts training facility at the Brighton Media Centre, Middle Street, were previewed at the launch. These will go live this month.

www.24hourmuseum.org.uk