The latest version of the PwnageTool 4.1 will allow you to Jailbreak the New Apple TV 2G. This will allow you to cook custom firmware for Apple TV 2G which will let you install third party apps from Cydia.
From the official blog:
AppleTV 2G users: Welcome to the JB family! Right now, about all you can do is command-line stuff via ssh. You also have afc2 available, so you can use tools like ifunbox to move files around. These are the *very* early days of AppleTV 2G jailbreaking, so it’ll take some time for JB app developers to come up with methods to use your AppleTV 2G from the remote, versus the command line. PS: Your ssh password is “alpine”…please change it when you can.
Follow the Step by Step guide below to successfully jailbreak Apple TV 2G:
Step 1: Download and Install the Latest version of iTunes available for here.
Step 2: Download PwnageTool 4.1 and iOS 4.1 for Apple TV 2G. Links to the download location given below. Move all these files to your desktop.
Step 3: Start PwnageTool and select Apple TV 2G as shown in the screenshot below:
Step 4: PwnageTool will now automatically detect the correct firmware for your device as shown in the screenshot below:
Step 5: Click on “Yes” when iTunes shows the following prompt:Advertisement
Step 6: PwnageTool will now create the custom .ipsw file for your Apple TV 2G which will be jailbroken.
Step 7: Now follow the following steps to enter DFU mode:
Connect your Apple TV with your Computer via microUSB.
Now reboot your Apple TV by holding down Menu + Down buttons together for around 6 seconds.
After reboot, immediately hold Menu + Play until you see the message in iTunes saying that Apple TV in recovery mode is detected.
Step 8: You will now have to restore your Apple TV 2G to this custom firmware 4.1 file. Start iTunes, click on your device icon from the sidebar in iTunes. Now press and hold left “alt” button (“Shift” button on Windows) on the keyboard and then click on “Restore” (Not “Update” or “Check for Update”) button in the iTunes and then release the “Shift” button.
This will make iTunes prompt you to select the location for your custom firmware 4.1 file. Select the required custom .ipsw file and click on “Open”.
Step 9: Now sit back and enjoy as iTunes does the rest for you. This will involve a series of automated steps. Be patient at this stage and don’t do anything silly. Just wait while iTunes installs the new firmware 4.1 on your Apple TV 2G. After the installation is done, your Apple TV 2G will restart automatically and you should now have a jailbroken Apple TV with full root access, running on iOS 4.1.