Sites fall into two categories: those that will report Tuesday's speech, and those that are already trying to predict the Chancellor's measures.
The large accountancy practices have had extensive Budget analyses on their websites for a few weeks. The pages give their opinions on the impact Gordon Brown's decisions will have on the economy and on business, in some detail.
For most people, though, the biggest draw will be the predictions on personal taxation and the Chancellor's usual targets of cigarettes, alcohol and petrol. The accountants look too at the prospects for the individual savings account (ISA) and possible tax changes for pensions and capital gains.
Deloitte and Touche's Budget 98 site is perhaps the most conservative but it scores well for its comprehensive scope.
Like most of the large accountancy firms, Deloitte is offering its views on what Tuesday will bring, along with an analysis of the impact. The site sets out what we already know, or is widely rumoured, including the new tax credit for working families and a 10 per cent lowest rate of income tax.
Price Waterhouse's site makes similar, reasoned predictions, and offers to send visitors the Budget by e-mail on Wednesday. This is a free service.
Coopers & Lybrand has the most interactive site of the big firms. It shuns straight predictions in favour of a racecard. Each plausible, and some less plausible, predictions have their own racing colours, and Coopers has given odds to each. Web users are invited to study the form and submit their own views as bets: the firm is adding visitors' odds to its site until Budget day. Coopers ranks a 10 per cent basic rate of tax as evens (readers give it odds of 3 to 1) but the accountants and the public agree that the odds on Gordon Brown abolishing Capital Gains Tax are 100 to 1.
Another interactive site is being run by the Institute of Fiscal Studies. The think-tank has a number of Budget-related pages, including its own Green Budget. Be your own Chancellor, however, is an interactive site that lets web users play with taxes, benefits and the public accounts to see whether they can balance the national books.
For the official line, most key government departments will be putting relevant parts of Mr Brown's speech on their own web pages as measures are announced. Information on tax changes will appear at the Inland Revenue and Customs and Excise; social security on the DSS pages, and changes affecting industry at the DTI. The Treasury itself will update its web pages, while the political perspective is covered on Labour's own site.
On the day itself these sites will be joined by newspapers and broadcasters, as well as on-line services' own internet news services. The on-line services are spending an increasing amount of time and money on bolstering their journalism, and Budget day is a good example of the way internet-based news is moving closer to broadcasting.
The Microsoft Network will be devoting a large proportion of its news coverage to the Budget on Tuesday, with analysis as the news breaks. America Online will also cover the Budget on its own news channel. Some financial websites are in on the act too: MoneyWorld has comprehensive analysis from its personal finance editor and one of the best sets of links to other Budget sites on the web.
The BBC always prides itself on its Budget day coverage and its site will be updated throughout the speech. Currently, however, the site still shows material from last year, but it is still one of the best-designed and well-rounded Budget resources on the net. It includes a few extras too, such as a Budget quiz. Independent television will be represented on the internet by Budget coverage from ITN on its home page.
The press, too, will be using the internet to put out its Budget day observations. The Financial Times already has a substantial Budget day site, although parts, including its interactive budget section, require web users to register on-line. This paper and its weekday sister will be joining the fray too, with Budget reports from Independent journalists available in the paper's on-line edition.
q Links: Coopers & Lybrand, www.uk.coopers.com/tax/budget-racecard/index.html; Deloitte and Touche, www.budget98.com; Price Waterhouse, www.pw.com/uk/budget98.com; Customs & Excise, www.coi.gov.uk.depts/GCE/GCE.html; DSS,www.coi.gov.uk.depts/GSS/GSS. html; Inland Revenue, www.coi.gov.uk.depts/GIR/GIR.html; DTI,www.coi.gov.uk.depts/GTI/GTI.html; Treasury, www.hm-treasury.gov.uk; IFS, www2.ifs.org.uk; Labour Party, www.labour.org. uk/core.html; Moneyworld, www.moneyworld.co.uk/budget98; MSN, www.msn.co.uk; BBC, www.bbc.co.uk/politics97/budget97/ budgetreports; ITN, www.itn.co.uk 'The Independent': www.independent.co.uk.Reuse content