Wolfram|Alpha search is a new specialized search engine that focuses on focuses on algorithmic answers for scientific knowledge. It easily beats Google or any of the other general search tools in its specialized area.
Even so, it's harder than it looks. Here's one example:
Result: 13.7 billion years
Wolfram|Alpha isn't sure what to do with your input
Looks like it still has a slight bias towards more precise terms like age vs old. It does seem to handle both "how big is …" and "what is the size of …".
On the other hand, this is quite impressive:
Result: 3.2 x 1060 planck times
But the following doesn't "work" quite as nicely:
Input interpretation: (planck length) X (diameter of observable universe)
Result: 1.6 x 10-40 planck times
Instead I have to search "planck length universe size" and then scroll down to "Ratios" section to see the answer I was looking for: 5.4 x 1061 planck lengths. Still, not bad.