Installer.app is a UIKit based package manager for the iPhone. It works by downloading packages over WiFi (wireless networking). It supports installing, updating and uninstalling applications. To install, simply copy the Installer.app bundle to your /Applications folder on your iPhone and restart SpringBoard (or reboot your iPhone) — an Installer icon will appear. It is recommended that SCP is used for copying, such that executable permissions are preserved.

http://iphone.nullriver.com/beta/