Buildings in the movie are named for makers of the movies that are being parodied. For example, John Hughes High School, "Anthony Michael Dining Hall" (Anthony Michael Hall), and "Harry Dean Stadium" (Harry Dean Stanton).
The original title was "Teen Movie", but this was ditched as the movie got more and more... un-teen. Then the title was changed to "NOT A Teen Movie" because of this. Then it was changed to "Not Another Teen Movie" because of all the parodies and the fact that there were so many teen movies before it.
The filmmakers couldn't get the rights to use footage from She's All That so they shot the scene with two different people (on the library set) and made the TV blurry so you couldn't tell.
Chris Evans (Jake Wyler) sang "Janie's Got a Gun" (by Aerosmith) at the stadium. During "Prom Tonight", the cast actually sings. No additional/backup voices were added.