iTunes users are using the program twice as long as RealPlayer and Windows Media Player, according to reports. Once iTunes overtakes RealPlayer later this year it will become the second most widely used media software player. Nielsen/NetRatings report that iTunes should have just under 30 million users, which is still far behind the 80 million unique users of the Microsoft Windows Media Player program.It's believed one of the major reasons for the popularity of iTunes are podcasts. Apple was one of the first major players to jump on the podcast bandwagon, by integrating a podcast directory in iTunes.
Apple iTunes to become second most used media player

DailyTech writes the number of iTunes users will surpass RealPlayer sometime this year.