AppleTVHacks.net puts together a 13-step guide on installing regular Mac OS X onto the $299 Apple TV. With USB keyboard and mouse support, the Apple TV turns into a full blown mini computer. The 1GHz CPU and 256MB RAM might be a little slow, but for only $299, it could be used as a nice little media center or an in-car media center.

Here’s the steps, a little hacking required:

1) remove the drive from the Apple TV

2) back up your drive! Make an image of it.

3) Connect the drive to a regular Mac (use a Firewire or USB drive dock)

4) Install OS X (Intel version) to the drive.

5) Boot from this drive, and set it up as you would like it. Make sure you do updates so it is at least 10.4.8.

6) Reboot to your normal OS X install.

Ok, you now have your fresh OS X install which will form the base of the customised OS X you will need for the Apple TV.

7) Remove mach_kernel from root of the drive containg the ATV install.

8 ) Replace it with the customised mach_kernel that you’ll find on Hackint0sh.org.

9) Replace /System/Libary/Coreservices/boot.efiwith the same file from your backup of the Apple TV OS drive (OSBoot partition).

10) Run bless:

bless –folder=/Volumes/OSBoot/System/Library/CoreServices –file=/Volumes/OSBoot/System/Library/CoreServices/boot.efi –setBoot

11) Delete all the Nvidia kexts (all beginning with NVD, there should be 5) from the target drive (in /System/Library/Extensions).

12) Transfer the drive back to the Apple TV

13) Turn the Apple TV on and cross your fingers.