Apple has sold more than 300 million applications to iPhone and iPod Touch users since launching its App Store in July, according to Apple advertisements that appeared this week in the New York Times and Wall Street Journal.

Some industry pundits have suggested that App Store, which now has more than 10,000 applications for sale, is just another passing fad, but Apple appears to be averaging 60 million App Store downloads per month.

In August, Apple CEO Steve Jobs told the Wall Street Journal Apple had hit the 60 million figure in the first month and suggested it could eventually become a billion dollar business.

"This thing's going to crest a half a billion, soon," Jobs told the Wall Street Journal in August. "Who knows, maybe it will be a $1 billion marketplace at some point in time."

However, according to Silicon Valley Insider, Apple has only booked between $50 million and $100 million from App Store programs.

In a Friday blog post, Silicon Valley Insider Senior Editor Dan Frommer noted that a goodly portion of App Store offerings are free, and that the average price of the top 10 App Store downloads is about $3.

Meanwhile, according to CNBC's Jim Goldman, Piper Jaffray analyst Gene Munster predicts that App Store's minimal operating expense will enable it to reach the $1 billion mark in 2009.

Some people scoffed when Jobs tossed the $1 billion figure out there in August, but it's starting to look more and more attainable. Not bad for a venture whose top-selling application right now -- Koi Pond -- features a bunch of goldfish swimming around a bubbly virtual lagoon.