PXL (pronounced ‘pixel’) is a package management tool for iPhone. It is still in the early stages, however. The primary component is a service called PXLdaemon, which runs on your iPhone; various client services (Breezy, iBrickr, Shimmer and so on) then speak to PXLdaemon in order to install or uninstall packages.

The goal is not only to have a reasonably extensible and sane format, but also keep the entire thing open source so that it can be a community effort to maintain and expand it.