P.I.A., there's critical thinking analysis tests, mechanical reasoning and also a psychological test (to which there are no right or wrong answers).
The test (CEP) is about 4 hours in total. There's not a whole lot you can do to brush up beforehand (other than blag some aptitude tests of a school or college careers officer, or someone else who might have them), but there is an article on the main PPRuNe site which outlines the selection procedure from aptitude test to final selection.
As Barhiggins rightly points out, answer the final section truthfully - they'll find you out later on anyway!
As for the spelling thing, remember the airline's code is EI, never call them 'AL'!!