If you want to find out the Lord Chancellor's salary or the population of Ukraine, and you have an up-to-date reference book at hand, use that. The Internet comes into its own with information that is changing all the time, and for finding people and learning about their experiences.
There are two problems with the Internet: sheer size, and the doubtful quality of much of the information. It is difficult to find answers to your questions, and when you do it is difficult to trust them.
Don't search unless you have to
If you can avoid going to a search site, you should do so. Keep your favorites (or bookmarks) in order and go back to the sites you have already found to be useful. Collect useful urls (web addresses) from documents and advertisements. If you are looking for a large corporation or a public body, you can try guessing its basic web name and you will probably be right: www.bbc.co.uk, for instance, or www.telegraph.co.uk.
If you are working on a story that is currently in the news and you want more information, you need a breaking news site or a site belonging to one of the news organisations. If you need something that is likely to have appeared in a formal reference work, go to one of the reference sites. After that, think about searching.
Broad or narrow?
If you want to know about a subject generally, using a range of documents or sites on the topic (colleges offering astronomy, European institutions in Britain, suppliers of bottled water, computer security) you might do better with Web directory like Yahoo, the Google Directory, the Open Directory or About.com than with a true search engine. These are lists of sites, selected and categorised by human beings. They don't have everything, but what they have will have been chosen by someone.
If you are really looking for the answer for a specific question, and you would ideally like to find just that on a single page, you should use a classic search engine, like Google, AllTheWeb or AltaVista. The most useful piece of advice I know is this: ask yourself what words are likely to be found in the single document you are seeking. Then type several of those words into the search box. If you get nothing, delete one and try again, and so on.
The point is to get a manageably small number of pages on your initial search. Then you can look through them, and if you don't find what you want, braoden your search by changing your words or removing a few. Finding that your search returns 1,345,676 relevant pages is a waste of time. Beware, you will not necessarily find what you want on your first page of results: in some search engines the top places are reserved for paying customers and those who know how to manipulate the system.
Finding someone to talk to
The Internet will find you plenty of documents, but journalism really requires quotes from real human beings. You will find lots of people discussing things all over the Internet. Then it's up to you to contact them and see if you can arrange to talk. Email interviewing is always second-best.
The main source of discussion on the Internet is in Usenet, also known as the "newsgroups". Traditionally you get to Usenet through a newsreader program, now built into your email program. But for searching information about subjects, you are better off using Google Groups, which provides web-based access to the system. Other discussions outside Usenet can be found through Topica.com and Yahoo groups.
Beware: there is no way of knowing whether the person you are reading about is what he or she seems. If you want to quote someone, it makes sense to ask for a telephone number. "Real" quotes also work better in print. To track down someone specific, you need a people search site.
You can, however, check on the ownership of a domain name hosting a specific page. You can also often determine how recently a web page was updated and how many other people link to it. Details on the Internet sleuthing page, which also has links to anti-spam sites.
If you are interested in getting deeper into Internet research, you should take a look at ResearchBuzz and perhaps subscribe to its email newsletter.
What a fool believes
Journalists pride themselves on their scepticism (which others often mistake for cynicism). Unfortunately, it sometimes seems to evaporate when faced with a well presented document found on the Internet. It pays to treat everything you see and everyone you meet online with the same healthy distance that you would treat someone in a pub bearing "genuine" secret documents.
Just as a reminder of the checks you can make, here is a fine piece from the Law Library Resource Exchange on Verifying sources on the net. Everyone should give these tests some thought.