Steve Jobs in an interview with the Wall Street Journal had confirmed that the kill-switch mechanism which gave Apple the capability to deactivate iPhone apps remotely existed.

Zdziarski had published a simple method to block Apple’s kill-switch mechanism.

Here is an even easier method to disable Apple’s kill-switch mechanism.

Steve Jobs had clarified that Apple would use the kill-switch mechanism only to remove a malicious program
— as an example a program that stole user’s personal data just as we
had thought. He had mentioned:

"Hopefully we never have
to pull that lever, but we would be irresponsible not to have a lever
like that to pull."

So I would not recommend iPhone users to disable this mechanism, but if
you are paranoid about Apple having control over apps running on your
iPhone then you can read on for more details.

Zdziarski had posted a simple method for blocking Apple’s kill switch, which needs you to jailbreak iPhone using iPhone Dev Team’s Pwnage Tool for Mac or WinPwn Tool for Windows and then add the following entry into /etc/host.

127.0.0.1 iphone-services.apple.com

An even easier method is to download the latest BossPrefs app using Cydia Installer on your jailbroken iPhone. After its installed, launch it from your iPhone’s home screen and choose the "Disable Apple App Killswitch". You can always revert back and allow Apple’s kill-switch mechanism in case you change your mind.