I used to think museum fatigue originated in the feet. Traipsing along corridors, through exhibition halls, souvenir shops and infotainment displays, the ache seems to spread from the feet, to the lower back, to the head, where a whirling confusion signals it's time to find the coffee shop.

It turns out that museum fatigue can be experienced at your own desk, without your feet ever touching the ground. Having browsed 10 museum websites - some beautifully constructed, with crisp illustrations and a choice of virtual tours, others more dull and pedestrian - my head was aching with that familiar confusion. There's simply too much of everything: too much information, too many beautiful works of art, too many galleries, too much to see and process. All right, my feet were fine so it was a lesser variant of the real thing, but still painful for all that.

Of course, as anyone will tell you, the essence of getting the most out of a trip to a museum is advance planning. Know what you want to see, and don't embark on detours. All very well, when intriguing sculptures and pictures inevitably entice the weaker-minded of us from the straight and narrow.

While browsing a museum on the web could be good preparation for the real thing, it's just as likely to tempt you down byroads.

The beautifully illustrated website of the Chester Beatty Library, now housed in Dublin Castle, makes an interesting starting point (www.cbl.ie). The collections include many important early Christian, Biblical and Manicheaen papyri. The library is one of the premier sources for scholarship of the old and new testaments. In the Islamic collection, a Koran, dating from 972, is the earliest copied on paper. One of the most treasured objects in the library is the Koran copied by the famous calligrapher Ibn al-Bawaab in Baghdad in 1001.

Before I drag myself away from this thoroughly enjoyable website, I should mention the listings of public events and the excellent page with links to other cultural institutions, both in Ireland and overseas.

The National Museum of Ireland does not appear to have a presence on the web. It's mentioned on the pages of various tourism websites. The opening hours, phone number, address, and a brief one-page description of the various collections can be found at www.visit.ie/countries/ie/dublin/top_at/23_nationalmuseum.htm

Heading overseas, the British Museum has a wonderful website offering a variety of "guided tours". The homepage is striking, almost scarily so, with its Shinto mask illustration seeming to stare malevolently out of the screen.

Tours include animals in the British museum, "Annuraaq: clothing of artic north America", "Cleopatra of Egypt: from history to myth", Kabuki theatre of Japan and a children's tour of the Anglo-Saxon world.

Taking the Cleopatra tour, images such a fragment of a basalt Egyptian-style statue of Ptolemy I (305-283 BC) can be enlarged to fill the entire screen.

The British Museum has the largest and most comprehensive collection of ancient Egyptian material outside Cairo, from the predynastic period to the Coptic (Christian) period, spanning more than 5,000 years.

Of course, looking at sculpture on screen has its limitations, but think of the savings on the airfare (www.thebritishmuseum.ac.uk).

Across the Atlantic, the website of the Metropolitan Museum of Art, in New York, includes online shopping as well as a facility to "visit" more than 3,500 works of art in its online collection.

There is a virtual reality tour featuring the American period rooms. The quality of the images is good and each work is accompanied by a description. So we learn that the orange tree that features in a portrait of Mrs Francis Brinley and her son Francis, 1729, was fashionable in Europe but an expensive rarity in the colonies. Its presence in the portrait reinforces the sitter's wealth. She holds a sprig of orange blossom, symbolising marriage and purity, while the fruit, a sign of fertility, emphasises her role as a mother.

Back in Europe, the Louvre has always been top of my list for museum fatigue. The website boasts a history of the Louvre - established in 1793, it is one of the earliest European museums - the collections, a virtual tour, visitor information and publications. The collections go from the ancient civilisations to the first half of the 21st century. The problem is one of choice.

Unfortunately, to "take full advantage" of the virtual tour, you need to download Quicktime. This can be done online, but loading it can take 20 to 30 minutes with a standard modem, according to the website. Of course, you need to stay connected to the internet during this time. Once the installation is complete, you have to restart your computer, and then return to the site to embark on a virtual tour.

My response is probably similar to that of many others... it's hardly worth the effort. So, no Louvre fatigue for me, this time.