People constantly bring up the fact that "Wikipedia can be edited by anyone!", but if you go and look at George Bush's Wikipedia page for example, you won't find the option to alter it. Plus, if you tried to alter a page and put a bogus fact in there, some die-hard fan would change it back in a heartbeat.
My advice would be not to solely rely on Wikipedia as a source. Use other places as well, trusted sources. If you see a page that says that 'George Unitt was born in 2047, created a time machine, and went back in time to murder Queen Elizabeth', then it's probably a load of rubbish. Probably.
Don't trust everything you read on Wikipedia, but don't discount it as a valuable source. It's a brilliant, incredibly useful website, as long as you use it properly.