Like the name says there are apparently 99 heroes, each from a different country, that are granted great power from certain jewels that have an Islamic origin. Each of them will have one of the 99 attributes of Allah. You can read the beginning of their story for yourself in the free origin issue. The comic has become so popular that there may even be a TV series in select markets by the end of this year. There is already a theme park in Kuwait based on The 99. Check out the motion comic intro:
If you're the kind of comic book fan that can name your favorite writers and artists, you may recognize a couple of names of the people who help bring The 99 to print. Apparently DC Comics is also well aware of The 99's popularity and is set to capitalize. There is rumor of members of the Justice League teaming up with The 99 in the near future. More after this brief commercial message.