Apple’s iPhone OS has more developers than any other mobile platform, according to a survey by research firm Ovum, with 81% of developers surveyed making apps for the platform. Not too surprisingly, BlackBerry is the #2 developer (74%), while Windows Phone OS is #3 (66%), and Google’s Android tagging along at #4. Nokia’s Symbian OS brings up the rear in the #5 spot with 56% of developers on the platform.

“iPhone OS is the clear favorite smartphone platform for developers,” said Tony Cripps, principal analyst for Ovum, in a statement. “While all five major smartphone platforms score well, it is BlackBerry OS and Windows Mobile that currently lead the opposition, rather than Android or Symbian.”

The survey was conducted among 217 developers.

The firm said that survey also showed that Research In Motion (RIM) has successfully made the transition from the BlackBerry being considered an Enterprise device to being mainstream. Ovum also said that Android’s 4th place ranking was unsurprising given that it was the newest competitor in the smartphone market.

“Overall, [the results] are also good news for Microsoft as it embarks on a new era with Windows Phone OS version 7.0,” the company said in its statement, adding, “This support for Microsoft smartphones is, we believe, reflective of the company’s eminence as a tools vendor, if not necessarily the user friendliness of its device platform.”

Truer words were ne’er spake.