Good guess, most people think that it's their crank but it is usually the bottom bracket. It would be a smart idea to get it checked out.

I've had the same problem (as mentioned in other threads), with the clicking. Bottom Bracket was replaced a few weeks ago and the noise is gone! My pedaling feels like new again .... What caused it? Cheap bottom bracket and accidently knocking the pedals against poles while riding.

Get your LBS to check it out, the BB's might need replacing and the 'cap' they run in might need replacing aswell. Also check that the chainrings on the crank are all tight.

The only other explanation for this would be a worn out chain ring tooth in contact with the chain.