The children Peter sees in the hospital are singing "Believe It Or Not", the theme from The Greatest American Hero (1981). That show was about a reluctant superhero who wasn't completely in control of his powers, a common theme with "Heroes".
In the scene where Angelia meets with Peter in his apartment you can see the helix symbol, or heroes symbol, in thumb tacks on the door frame leading into the kitchen. The symbol is especially clear at 10:24.