During the conference call yesterday, Steve Jobs revealed that the 200 millionth application would be downloaded from the App Store sometime today.
Apple previously revealed that the App Store had delivered over 100 million applications on September 9th. The most recent numbers suggest there has been an acceleration of downloads since that time.
Jobs gave no hints as to the revenue currently being generated by App Store sales, though back in August detailed that Apple had been selling an average of $1 million a day in applications during the first month.