Wikipedia offers some of the best online resources for research of your interest. You can use Powerset to search articles within wikipedia at http://www.powerset.com Powerset indexes the whole widipedia website and has a very intuitive and powerful interface. It's definitely the number one website I will go to do any kind of school research project.
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Some sites I like:
News from a non mainstream viewpoint:
http://www.youtube.com/user/TheRealNews

finance:
http://finance.yahoo.com/

cricket:
http://www.cricinfo.com/widgets/

social networking/messaging:
http://friendfeed.com/
http://twitter.com
http://flickr.com

uk/world news:
http://news.bbc.co.uk/

US politics aggregation:
http://www.memeorandum.com/

celeb news aggregation:
http://www.wesmirch.com/

world news aggregation:
http://news.google.com/

latest adam curry conspiracy stuff:
http://drop.io/dailysourcecode

picture blog:
http://damncoolpics.blogspot.com/

best of the web:
http://digg.com/
http://buzz.yahoo.com/
http://www.reddit.com/

best of tech:
http://www.techmeme.com/
http://slashdot.org/
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It really depends on what kind of research you are looking for. If you are looking for news articles or product reviews, I would start with Associated Content (http://www.associatedcontent.com) If you are looking for scholarly work, then I would try Google Scholar (http://scholar.google.com/) It will search journal articles for you. One problem, though, is that a lot of journals require subscriptions. If you are a student at a university, then chances are that your university has a subscription and you can get the article on campus. However, I have also found where scholars have posted their papers on their own personal websites, as well, allowing you to access the article for free.
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What kind of research? The fastest is "google (what you look for) site: gov" for all statistics; "CIA" factbook for all foreign countries (government,industries etc); "google (what you look for) site: edu" for anything you study, "google scholar" for scientific papers. For what people think of neurology, politics, and whatever you have in mind, look for good bloggers (search "bloggers (what you look for)"
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Go to the website of your local library and look for a "Research" link. Most libraries subscribe to peer reviewed article databases which provide access to full papers (not just abstracts), which would otherwise be too expensive for an individual to subscribe to. If your local library doesn't have any such subscriptions you can usually get a library pass to a local university which will have those subscriptions.
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www.cliffnotes.com has a lot of good information for free.
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My favorite site is Answers.com. It gives you dictionaries, encyclopedias, thesauruses, Wikipedia, a Mahalo Answers-like system (sans tips,) editorials, shopping results, et cetera, all on one page.
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Ask.com is very helpful for pretty much everything.
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Apart from the sources consistently listed above (Google Books, Google Scholar, Wikipedia as jumping-off points and orientational aids), some of the best and most comprehensive sites include:

Project MUSE (http://muse.jhu.edu/) here you can search for scholarly articles across a wide range of disciplines, with emphasis on the humanities. If you attend a university which subscribes to their service, you will be able to view the full text of articles as HTML or download them as PDFs. But even without a subscription, you'll find relevant titles with full bibliographic information, so that you can get the articles from a library or by other means, along with (in many cases) abstracts for the articles. This is truly an invaluable resource.

JSTOR (http://www.jstor.org/) is a similarly structured site, also offering access to full-text articles for subscribing individuals or institutions. Unfortunately, though, you won't be able to search without such access.

There are also a number of commercial services that are similar in nature, such as ProQuest (http://www.proquest.com/) which offers a variety of specialized and general subscription models. (Not cheap, though!)

One of the first places I look when doing any kind of research, however, is consistently free and offers not only textual materials but also multimedia (audio, video, etc.): the Internet Archive (http://www.archive.org/) Here you can find complete (public domain) books, films, audio recordings, among other things. Especially for historical research, this is a great place to check. Moreover, with their so-called "Wayback Machine", you can access cached versions of Web pages that have changed or no longer even exist!

You might also like to try the Free PDF Search Engine (at http://www.pdfgeni.com/) I just discovered this recently, but I've been quite surprised by the usefulness of the site, which has turned up some otherwise undiscovered gems while doing research for my PhD dissertation.

These, of course, are only a few of the uncountable resources available. But I've chosen those listed here because they are general, all-purpose sites that will be relevant to all sorts of research--not too specialized, but offering materials that will be relevant and credible in a variety of fields and disciplines.

I hope this helps...
Source(s):
http://muse.jhu.edu/
http://www.jstor.org/
http://www.proquest.com/
http://www.archive.org/
http://www.pdfgeni.com/

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About.com, ehow.com, and delicious are all good ones to find great information.
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wikipedia.org
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To get scholarly research, and be able to get it without needing a database login, I use google scholar. It's a wonderful site and you can specify to search only full-text documents. Note that this is different that google books.

If you are just looking for general information, I find that Wikipedia is really not that bad of a source. Teachers complain about it because anyone can edit it, but 99% of the time I still find that is the most up to date and relevant to the information I am looking for. Do not discredit a community based product. After-all, Mahalo is community based too!

For tech news, I tend to visit Lifehacker, Techcrunch, and http://googlesystem.blogspot.com/ , a blog on google's latest accomplishments.
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