How many species of sharks are there in the today?

About 365 if I remember correctly (one for each day of the year).

And one extra species in leap-years.

The taxonomic splitters get their way once every 4 years, then the groupers trim the numbers back again!

As much as the previous answers were far more entertaining as resident shark expert i feel the need to be pedantic! The actual number of modern shark species is somewhat higher than advertised. There are over 800 species of Elasmobranchii (the Sub-Class that includes both the batoids and sharks) 463 of which are sharks and 337 of which are batoids (the groups that consist of rays and skates). Then there are the fossil sharks and rays that bring the number of species up to way over 1000!