The Linux 2.6 kernel has been ported to both generations of iPhones as well as the 1st generation iPod Touch. 

This is a major event in the iPhone world as it has been reverse engineered enough to allow a new OS to run alongside the normal iPhone OS. As of now there is no support for the touchscreen, accelerameter and most other features. Just running the Linux kernel itself is a huge achievement.

Here is part of the post from the linuxoniphoneblog:

 
I’m pleased to announce that the Linux 2.6 kernel has been ported to Apple’s iPhone platform, with support for the first and second generation iPhones as well as the first generation iPod touch. This is a rough first draft of the port, and many drivers are still missing, but it’s enough that a real alternative operating system is running on the iPhone.

What we have:

- Framebuffer driver
- Serial driver
- Serial over USB driver
- Interrupts, MMU, clock, etc.

What we have in openiboot (but hasn’t been ported yet):

- Read-only support for the NAND

What we don’t have (yet!):

- Write support for the NAND
- Wireless networking
- Touchscreen
- Sound
- Accelerometer
- Baseband support

The current userland we’re using, in the interest of expedience, is a Busybox installation created with buildroot, but glibc works fine as well, and we’re going to build a more permanent userland solution.

We’ll have to see how far this goes, but I’ve got to say, if they got Linux to run on an iPhone with full touchscreen capabilities… well that would be amazing.

Definitely pay some attention to this blog in the future: linuxoniphone

Here is a video of Linux on the iPhone

iPhone Linux Demonstration Video from planetbeing on Vimeo.