Apple put an interesting step in the battle against jailbreaks for the iPhone. A system that enabled detecting wether a phone has a jailbreak, has been removed.
With a jailbroken iPhone, it is possible to install an app outside Apples App Stor. You'll risk downloading malware. A danger you can take, but for business use, it's also the employer that's in risk. The detection system that is removed now, helped system managers to see wether a jailbreak was done for one of the devices under his control. Now, system managers loose this possibility to monitor their network.
Jailbreak
According to Apple, it will still be possible to detect a jailbreak. Jailbreaking your iPhone is still against rules made by Apple. With every lauch of a new version of iOS, like the recent version 4.2, Apple tries to make known possibilities of jailbreaking impossible.
Source: Engadget