You know why Sesame Street has felt it necessary to do a song-and-dance about "iPogo Stick" apps? Like their other themes of bullying, violence and err, obesity, parents ignoring their children for Angry Birds playtime has become a real problem.
Key to the trademark issues - Likelihood of confusion and the fair use doctrine. It's highly unlikely that someone will confuse the source of Sesame Street (or at least Sesame Street fictional products) as the same source of iPhones (and black turtle necks and new livers). Furthermore, fair use doctrine allows for some leeway in commenting on another brand by using their trademark in a non-confusing manner.
so yes, @joep1984, there IS a lawyer for that . . . (as I skat my way out the door on a "magical, just truly amazing" pogo stick)