Well on the way to showing just how superbly the web can provide new types of practical mapping services, Multimap offers a comprehensive street map of Great Britain and competent ones of Ireland and Europe, which can be viewed at different scales so that eventually such features as a step-by-step travel direction-finder (which already works in Great Britain) and local information for anywhere in the world will be available. Easily accessible extras such as aerial photographs and a London Tube map add value for the directionless.

www.ordnancesurvey.co.uk

This outstanding site gives access to the vast banks of authoritative material at the disposal of Britain's national mapping agency. As well as explaining how to read OS maps and helping ramblers plan their trips and download relevant maps, it covers a range of teaching activities relating to mapping and gives clear instructions on copyright (the OS took the AA to court earlier this year and won millions, so be careful). This is achieved with such simplicity, it makes one rather proprietorially proud. There is a Welsh-language mirror site, too.

www.mapquest.co.uk

This British offshoot of the leading American mapping site finds maps and gives directions effectively. As with Multimap, you can download maps to a handheld organiser using AvantGo software (Multimap also collaborates with Psions). It loses out to its rival in not yet recognising one-way streets, but its journey breakdowns are every bit as friendly. Its American service lives up to expectations, and it gives directions in Europe, too. Time will tell whether its wide user base will give it extra clout, but at the moment it is second best for Brits.

www.maps.com

More useful for real travellers than for those wanting help with homework. There are basic maps, weather maps and currency converters, as well as European directions, but Maps.com's real selling point is selling. It has a huge range of atlases, country maps, route maps and city maps, from Honolulu to Tallinn, as well as desktop globes, travel guides and antique wall maps. Prices are reasonable (£15 for a wall map based on a 16th-century map of London), but shipping is expensive unless you are buying several products.

map.net

The geographical imagery of the web (addresses, sites, etc) suggests that cyberspace needs its own map. This attempt takes Antarctica as a template and divides it into territories based on common topics. Homing in by subject makes for an intuitive and effective search engine, which took me quickly, for instance, to 14 Leyton Orient FC websites. The 3-D version does not work smoothly yet, but swooping through sites represented as buildings, with Amazon and the BBC as skyscrapers and smaller rivals as houses, is wonderfully appealing. One to watch.

www.nationalgeographic.com/maps

Perhaps the best way to do justice to this site is to say that it lives up to the words of National Geographic's founding editor, who said: "A map is the greatest of all epic poems. Its lines and colours show the realisation of great dreams." As well as an up-to-date political, climatic and geographical atlas, it hosts fine historical maps (railroads, exploration, battles), a map of Mars and an atlas of endangered species. The site is let down by a confusing layout and slow downloads, but if you have time, it will repay you.

www.streetmap.co.uk

Like Multimap and Mapquest, this has a complete street map of mainland Britain but without (as yet) a Tube guide, aerial photos or directions. It is searchable by street name, grid reference and postcode, and is nicely put together. It is hard to be sure of details without checking every postcode, and there are inevitably parts of the country where it outperforms its rivals, but in what looks like a cut-throat marketplace, it must provide more content if it is not to be pushed out.

www.worldatlas.com

This odd but enormous mix of links and maps is one of the best possible first steps for anyone hunting good basic geographical data (Where is it? What is its capital, flag and currency?) on any country under the sun. WorldAtlas is endearingly bullish about its powers - the subtitle to its Geography Question section is "We have the answer" - but it does cover such disparate areas as climate, bodies of water, earthquakes, populations and embassies. An essential, if chaotic, reference bookmark.

www.getmapping.com