Good new for iPhone owners who jailbreaked their phones. The alternative App Stores Cydia an Rock your Phone will soon merge. Some options that were only available in Rock your Phone before will come to Cydia.
The merger means that Rock your Phone will cease to exist, and Cydia will move on. Rock's developers will join Cydia, bringing some functions that were unique to Rock your Phone to Cydia in the future. One of thee functions is backing-up installed Apps, not yet possible in Cydia, but possible in Rock your Phone, will come to Cydia soon.
Jailbreak
Jailbraking your iPhone is against rules made by Apple. With every lauch of a new version of iOS, like the recent version 4.1, Apple tries to make known possibilities of jailbreaking impossible. Those who updated their de iPhone 4, 3GS en 3G to 4.1 can't jailbreak their phone for now, but that won't take long.