The Good
There are few places better to go to than Wikipedia for trivia type information. Want a the roster of the Boston Red Sox? Need a list of every episode of Family Guy? How about a biography of Paris Hilton? Wikipedia has all that and more. However, don't think that Wikipedia doesn't have a legit use for your scholarly research.
One of the best uses of Wikipedia is as a tool to familiarize yourself with a topic. You should never begin researching blind. If you don't know about your topic, look it up. After reading the Wikipedia entry, you'll have an idea where to begin your research. Is there a lot of historical information? Then you'll probably need a book. Is a hot and current topic? Then you'll probably need a journal article. Also, look for keywords and spelling.
Finally, pay attention to the references and notes at the bottom of the entries. Most Wikipedia articles cite their sources. There's absolutely no reason why you can't investigate those sources and use them for your research.
The notes and references in Wikipedia can be very helpful.
The Bad
The biggest problem with Wikipedia is that anyone can add, edit and delete entries. Remember: when you do research for you paper, you want scholarly sources -- those written by experts in their fields. Wikipedia entries are not scholarly. We know nothing about the people who write them or their credentials.
There's also a lot of bias in Wikipedia. It is quite common for people to alter the entries of topics they don't agree with and change them to reflect their beliefs or to change the original entry to discredit it. They might change an entry to make the topic appear better than it should. Sometimes, people just vandalize entries for no apparent reason. Some entries are so heavily vandalized that they require extra monitoring and higher levels of security.
"Wikipedia is increasingly used by people in the academic community, from first-year students to professors, as an easily accessible tertiary source for information about anything and everything. However, citation of Wikipedia in research papers may not be considered acceptable, because Wikipedia is not considered a credible source."