iBrick

Software kits 

iNdependence - iNdependence is a Cocoa-based application for Mac OS X which provides an easy-to-use interface for jailbreak, activation, SSH installation, and ringtone/wallpaper/application installation on your iPhone. It’s open source under the GNU v2 license. http://code.google.com/p/independence/

AppTapp Installer.app -  Installer.app is a UIKit based package manager for the iPhone. It works by downloading packages over WiFi (wireless networking) or EDGE. It supports installing, updating and uninstalling applications from multiple sources.

Sites

ModMyiPhone - Discussions and Wiki Knowledge Base. http://www.modmyiphone.com/