Derek at Pop Life emails to say that the rap kid's T-shirt must be derived from a Mobb Deep lyric on The Infamous:

"It's not where you at kid,
It's where you from,
'Cause where I'm from,
Niggas carry nothing but the big guns"

And a whole bunch of people emailed to point out that "Ian Brown's maxim" actually comes from Rakim, in "I Know You Got Soul":

Now if your from Uptown, Brooklyn- bound
The Bronx, Queens, or Long Island Sound,
Even other states come right and exact,
It ain't where you're from, it's where you're at

According to Steve Kiviat, it also appears in "In the Ghetto" (Thrifty Rakim! And why not, a good line's worth recycling), viz :

Going for self wit a long way to go
So much to say but I still flow slow
I come correct and I won't look back
'Cause it ain't where you're from, it's where you're at

and several other points in the track

So evidently Mobb Deep are playing on that hip hop quotable, it seems fairly unlikely they're massive Stone Roses fans.

If memory serves, Ian Brown said it at the press conference before Spike Island, someone was asking him about the Manchester scene, and he says "it's not where you from, it's where you're at, man". Or maybe he said it onstage during that ill-starred concert.

At the time I thought this was a cool remark as I was opposed to the whole idea of scenes and the mystique of certain cities (specifically Manchester, when really there was only the Roses and the Mondays carrying the whole baggy movement). Well of course since then I've revised my thoughts on the subject quite a bit.

"Where you're at" and "where you're from" both seem to have things in their favour, though. And it's also the case that whatever "at" you're, er, at, will always carry traces of the "from" that was your departure point. C.f. Puff Diddy as sampled by Roll Deep: "sometimes I don’t think you motherfuckers understand where I’m coming from, where I’m trying to get to.” Bryan Ferry with the traces of Geordie accent lingering in his croon. David Sylvian growing up in Catford, his real name David Batt. Sun Ra's belief that he's from Saturn inseparable from the alien-ation of being in born in Birmingham, Alabama.