All kinds of background info sites here, to help you plan your trip.
Are you a regular traveller? A frequent flyer perhaps? Like me, are you often confused, or even angry about inconsistencies in what you're allowed to carry aboard an aeroplane? See here http://www.dpsoftware.co.uk/airlines/ to answer some of your questions. It lists allowable weights and dimensions of carry-on luggage for most airlines.
Some of these are related to motorcycling, but most are interesting travel links to places around the world.