what do you mean by children?
if you mean little kids, then old navy, abercrombie, jcpennys, target, kohls... a lot of stores specifically for kids around too, old navy is good department store
for teens
american eagle, forever 21, h&m, hot toic, pac sun, hollister, abercrombie and fitch, american apparel, urban outfitters... you can also get clothes at old navy, target etc. but that's just kind of like getting your clothes at tesco!