Large surveys, both using ground or space-based facilities, are providing an increasing 
number of candidate transiting extrasolar planets. A quick solution of the light curve is 
found to be very useful to discard false candidates as well as to provide good initial 
elements for a detailed analysis of the data. The obtention of a fully analytical solution 
of the light curve of extra-solar planetary transits has allowed for the derivation of 
simple expressions to estimate the best elements for the radii of the star and the planet as 
well as the inclination of the orbit. The method is presented together with its application 
to all up-to-now known cases of transiting extra-solar planets. Further examples will be 
given showing the application of the algorithms to the COROT search for transits.