Yes its true , Apple has reached half-million Application level that is approved one and its claimed that Angry birds is top-most paid app of App Store.

According to these ReadWriteWeb Folks:-
1 It would cost $891,982.24 and over 7 terabytes to get all available applications.
2 Approximately 36% of all apps are free and paid apps have an average price of $3.64
3 Angry Birds released by Chillingo and developed by Rovio has held the number 1 paid spot more than any other app at 275 days total.