We usually encourage people to make Wikipedia their first stop when checking a source. But depending on the type of source, you may want to check out coverage in Google News, Snopes, or Google Scholar. Here's how.
Sometimes Wikipedia won't have data on people or organizations you want to know more about. Google News is a good next stop:
Using Google News to Check a Source
(Remember that after you find a news source with information about your organization or individual you may want to use the "Just Add Wikipedia" technique to make sure the news source you are looking at is legitimate. Google News usually has a better set of results than regular search, but not everything in there is trustworthy)
You can try this "Just Add Snopes" technique when Wikipedia doesn't work for a possible hoax, satire, or "fauxtire" site:
If a site publishes a lot of hoaxes or misinformation, it is probably not trustworthy.