Now that the controversy with Sydian has been cleared :D :
If you want to try out Pokémon Green in English, just go here: http://www.romhacking.net/hacks/876/
Note: This is a patch for a ROM of Pokémon Red, it's the same link I posted before.
You have to apply the .ips file contained in the zip to a clean Pokémon Red ROM, which you have to get somewhere else. To do so use "Lunar IPS" for example.