That's what someone says at the LGBT blog Pam's House Blend (and Pam seems to have accepted the claim since she front-paged it)
He claims that it started because of the May 20, 2007 Family Guy Episode "Meet the Quagmires," which parodies the classic time-traveling movie Back to the Future.
In the movie, Michael J. Fox is asked to play "something that really cooks," so he plays "an oldie where I come from," Johnny B. Goode, and the band-leader (Marvin Berry), calls his cousin "Charlie" and tells him "You know that new sound you've been looking for? Well listen to this!" then holds the phone out.
In the episode, Brian is asked to play another one, so he says "This is a song by a gay guy" and then plays Rick Astley's "Never Gonna Give You Up" [Astley is presumably not gay as he has a wife and daughter] and "Marvin Astley" calls his cousin "Rick" and calls the sound "mediocre, generic" and does basically the same thing.
The claim made is that this episode started the rickrolling phenomenon (where you pretend to link to something interesting but instead link to a video of Rick Astley's "Never Gonna Give You Up").
The episode probably helped spike the popularity of rickrolling. However, it almost certainly didn't create it, unless it was created by a Family Guy writer/Fox employee.
Because the phenomenon existed before May 20, 2007.
This rickroll'd video was uploaded May 15, 2007
Rickrolled.com was registered May 14, 2007 per a whois search.
Someone asked about it on May 16, 2007 and it started March 29, 2007 on a 4chan board where someone claimed it was a "GTA4 gameplay vid"
So no, it's not homophobic.