My youngest son often asks whether a particular object in the sky is a planet or a star. If it's a planet, of course, he wants to know which planet. Some of them I can pick out. Venus isn't usually rocket science (no pun intended). Mercury can be a little tougher. Fortunately, I stumbled across a video blog from Wolfram Alpha yesterday that describes their efforts specifically in the field of astronomy.
Can you imagine what a search for "planets" would give you on Google? The same search on Alpha was downloadable as this PDF. A search for "big dipper" was equally useful and, like all Alpha searches, provided bibliographic references as well.
Alpha certainly takes some getting used to. A search for "what planets can I see at 10:00pm in the United States" yielded nothing, while the same search on Google brought me to hubblesite.org with a Flash animation of objects visible in the night sky (true, the link was outdated, showing me January's sky, but a bit of looking on Hubblesite led me to the July version).
Learning curve and limitations aside, Alpha continues to impress with the concise way in which it returns useful information.