At the end of last week, Apple turned from an iPhone app supporter into an iPhone app killer, as it decided to knock down the NetShare tethering application just hours after its release, without giving any explanation.

The application, developed by Canadian company Nullriver Inc., allowed users to transform the iPhone into a modem and provide Internet access to their PCs. According to the developer, their app was in full compliance with Apple’s developer guidelines.

It appears that the app was taken down, put back up, then taken down again, all without any explanation. As Nullriver wrote on their website, they are still “not quite sure why Apple took down the NetShare application yet, we’ve received no communication from Apple thus far. NetShare did not violate any of the Developer or AppStore agreements.”

While several handsets offer tethering possibilities, carriers usually charge monthly fees for the service. NetShare offered it for just $9.99. However AT&T, which is the official iPhone carrier in the United States, does not officially permit tethering for the iPhone, although it does permit it for other devices for a $30 monthly fee.

NetShare practically runs like a proxy for the notebook, allowing the notebook to connect to the Internet by using the phone’s data network. Apple did not respond to Nullriver’s demands for an explanation so far.

“We’ll do our best to try to get the applications back onto the AppStore if at all possible,” Nullriver said on August 1. “At the very least, we hope Apple will allow it to be used in countries where the provider does permit tethering.”

While Nullriver is praying for its application to return to the App Store, those who have already tried it found it useful, rating it high on the App Store.

Questions on who is responsible for blocking the application, Apple or AT&T’s policy, are still hard to be answered, since none of them commented on the story.

Which takes us to another problem: iPhone users got their hands on an app they like for a few hours, then it was gone. Won’t this drive consumers to jailbreak their phones, and put an end to Apple’s complete control over what apps they may use? Not to mention they would get them for free… That is not an encouragement, but Apple’s wall of silence is…

In July this year, Apple launched the App Store, with over 500 applications for the iPhone, and invited developers to submit their creations, while Apple retained 30 percent of the profit. Users can download free applications at no charge to either the user or developer, or purchase priced applications with just one click.

Just days after the 3G iPhone’s official launch, the iPhone Dev Team released a jailbreak took for iPhone 2.0, enabling iPhone and iPod users to jailbreak software for their devices.

So the problem that comes to our mind now is: yes, there are free applications on the App Store, but there are also lot of apps we have to pay for, and when one of them gets pulled out without any explanation, won’t it make users turn to the Pwnage tool?