hmm
as far as gta4 goes..
www.gtavicecity.com is the preview.
as far as gta3 goes.. the websites, commercials, etc, on the radio stations are all "real" ..manufactured by rockstar entertainment. check 'em out, like
www.petsovernight.com "Delivering Little Bundles of Love, in a box, directly to your door ..meow!
...and I'm expecting just as much Debbie Harry in GTA4 as in GTA3 on Flashback! heh