The following wiki article describes how to install GCC on an Apple TV.
One of the main requirements is that you have access to an Intel Mac with Tiger with Xcode tools installed.
As i've said previously, I don't own any Apple computers, nor do I know anyone who has a tiger box.
I found a way to workaround this issue :-
There is a 1.37 GB OS X tiger VMware image floating around on the internet that you can get using your favorite torrent tool.
Its name is something along the lines of :-
VMWare image for MacOX 10.4.8 (created from JaS AMD-Intel-SSE2-SSE3 with PPF1 & PPF2 image).
The guy that created this image used VMWare Workstation ACE Edition 6.0.2 build-59824. The vmware image is compressed in a file named: VMMACOS.7z
Note, the image was also created on a 64bit Windows box with virtualization enabled for the processor (in the bios). To run this image, you need the same setup (Windows XP 64, and virtualization support enabled in the bios).
If you don't have XP 64, search for 'Superior XP 64'.
Unfortunately the above Tiger VMware image does not have XCode installed, so you have to install it!
You can get XCode free from apple by registering a free account on the Apple Developer Connection website.
You want to download XCode 2.2.1.
Install the above on to to the Tiger VMware image and you should be good to go.
The only other issue was getting access to gcc-intel-bin.tar.gz
I couldn't find it anywhere.
Here are some links to gcc version 4.3.0 20080125 (experimental) (GCC) :-