Evidence #1
Hmmm what could AT mean??
Hey, whoever these "AT" guys are, they sure like PSO!
Evidence #2!
That face sure looks familiar! (hint hint: Dreamcast)
After a bit of espionage action, I found their hideout!
Evidence #3!!
It's the ATHQ Bus!!
Hehehe. Hope you guys like my custom JGR tags. Got a bit bored.
Oh and everything was made using the in-game graffiti tool.
It's pretty darn neat once you know how to use it.
Anyway, since its an old game, they took down the official site. So I couldn't go browsing other sites using the in-game internet browser.
Meaning, I couldn't download any images. I had some stuff photoshopped and ready to go but I couldn't transfer it to the game

And the answer for #2 is: from the cover of the PSO v2 booklet.
--d-_-b