Fast Sn0w is one of the best options going around when it comes to jail breaking an iOS device. The latest release by the development team is yet another counter retaliation against Apple’s determined campaign against jail breakers, many of whom continuously defy Apple by jail breaking their iPhones. Recent legal rulings show that courts favour jail breaking, but Apple has responded by cutting off support and locking out devices with each additional update.

The advantages of jail breaking include the ability to use it on other carriers and install apps that have not been approved by Apple. However, once you have done this you can forget about updating the iOS software or taking it to Apple for tech support.
The latest jailbreak update is a Fast-Unlock mechanism. According to recent reviews, Fast Sn0w’s 0.9.6rc15 jailbreak is quite safe and secure. However, more time is needed to properly access this claim. Judging by their reputation, it seems like a safe bet.
This update will also support untethered jail breaking. If you are planning to unlock your iPhone 4 via Windows, you need to use Sn0wbreeze and if you have a Mac, then you will need to get your hands on the PwnageTool.
Apple does not plan on standing by the sidelines as new and more effective jail breaking techniques are proliferating at an increasing pace. In fact, it announced that the iOS 5 would specifically target jail breaking and seek to seal weak spots in the operating system. If we know anything from this war, it is that this is going to continue for a long time.
The only ones not having this problem is Android and that is because it is an open source project. Perhaps Apple has a little to learn from all of this. Perhaps it could allow users to tinker around with some common features while maintaining control over the major features of the iOS.