Yesterday at the urging of a friend, I ordered “Your Brain at Work” by David Rock on my iPod touch via the Amazon Kindle app. In doing so, I became one of many people who are helping the iPhone become more than just a phone. It’s latest role: e-reader.

Book-related apps saw an upsurge in launches in September, according to a survey conducted by Flurry, a San Francisco-based mobile application analytics company. So much so, that book-related applications overtook games in the App Store as a percentage of all released apps. The trend isn’t an aberration. In October, one out of every five new applications launching on the iPhone was a book, Flurry said.

Why is this important?

Because from August 2008 to the same month in 2009, more apps were released in the “games” category than any other and, as a result, the iPhone (and iPod touch) became a new handheld gaming platform, one that impacted Nintendo DS. The Japanese game device maker acknowledged that the iPhone and iPod touch were among the reasons why its profits declined drastically in the most recent quarter.