I looked around and found some guys discussing the blink codes for an Xbox on 2005, so they are most likely discussing the first Xbox.
* Solid red, overheated.
* Flashing green, bad bios load.
* Flashing red-orange, bad video output
* Flashing red-green, system faliure (can be alot of things)
Here was where I found the [http://dealdatabase.com/forum/archive/index.php/t-31252.html|thread] if you wanted to read through their discussion. As long as its not flashing red and green, it would be safe to assume your Xbox is overheating.