Before the race starts, a message saying something like, "This is being broadcast on Gotham TV," is displayed. This is your cue to seek that achievement. To get the GTV achievement, you have to place in one of the top three spots in that race.
Edit: Oops, sorry. I was thinking of the Gotham Hero achievement. (IMG:http://images.xbox-scene.com/forums/style_images/oldx/folder_post_icons/icon4.gif)
For the GTV Sports Fan achievement:
QUOTE(twistedsymphony @ Dec 9 2005, 06:28 PM)

Gotham TV Sports Fan - 15GP
Watch ten races on Gotham TV (they do not have to be all the way through) and save a replay of one of your own races.
You wont receive the achievement immediately but next time you login. Also the "Achievment Unlocked" icon won't ever pop up so you'll have to check yourself to see if you've earned it yet.
When I got mine, I remember I just left the thing on GTV and went to do something else since it plays GTV continuously without your input once you get to that screen. I came back to the game after about an hour or so which was probably enough time to have at least ten full races play without interruption. I turned it off, and later when I went to play on Live again, I received the achievement. At some point before that, I had saved a replay of my own.
This post has been edited by metaldevil: Jun 19 2006, 08:54 PM
QUOTE(Adam6 @ Jun 19 2006, 04:20 PM)

Also why we are on the subject, complete your little guide on how to get the Gotham Hero one please!
It's the same thing I said before:
QUOTE(metaldevil @ Jun 19 2006, 03:43 PM)

Before the race starts, a message saying something like, "This is being broadcast on Gotham TV," is displayed. This is your cue to seek that achievement. To get the GTV Gotham Hero achievement, you have to place in one of the top three spots in that race.
I think you'll get this as soon as you cross the finish line in 1st, 2nd or 3rd place.