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Pokémon Vega is probably the highest regarded of all foreign-language Pokémon hacks. But until now, you couldn't experience it in English. That's where we come in.

We have fully translated Pokémon Vega, and it is now available as a patch for English Fire Red, here:
When linking the download to others, use this page (or the Pokecommunity thread) instead, since it will always have the current version of the patch.

Who's "we"? There's a credits file included with the patch.
Also included is a plot summary of the prequels, Pokémon Altair and Sirius, so you can jump right in without having to play one of those lower-quality hacks. If you absolutely must, they're here:

Features of this hack:
A fully new region, the Tohoak region!
181 new Pokémon, plus 56 Pokémon from newer generations!
70 new moves, plus 87 moves from newer generations!
Impressive custom music! (Full OST download here)
Rematches with almost all important trainers!
An extensive postgame, including a battle facility!