In Generation V, it (the probability of obtaining a shiny via the Masuda method) is boosted even further from 1 in 8,192 to 1 in 1,365.3.
So these are your chances of getting a shiny via the Masuda method.
If, however, you're using the Masuda Method to breed, (the shiny charm) reduces it from 1 in 1,365.3 down to 1 in 1024.
This is your chance of a shiny by using the Masuda method while having obtained the Shiny Charm for catching every Pokemon in the National Pokedex (bar event legendaries).
Serebii on shinies