It's funny, huh? Everyone is here, but people are here. It's because "everyone" is a singular collective noun referring to a group. The same is true of "family", and it's proper use is, "My family is at Disneyland." The plural of family is "families", and "Families are at Disneyland."
"People" is the plural of person, so it's "People are..." and not "People is..." - unless you're referring to the word "people", like this sentence.