iPhone 3.0 upgrade is available for general use now. This upgrade will give you lots of features which were unavailable in iPhone so far. You can get new upgrade by connecting your iPhone to iTunes and upgrade to the latest firmware.
If your are using jail broken iPhone then don’t do that. It’ll make your iPhone unusable for you. The good news is that iPhone-dev team has released PwnageTool 3.0 for mac OS. If you are using first generation iPhone then you can upgrade your iPhone to new firmware.
If you don’t have a mac system or you have iPhone 3G them wait for some more time. Team is working hard to get QuickPwn and PwnageTool on mac and windows.

You can download current release from here.

More information can be read from iPhone-dev blog.