emo is a trend that used to be pretty popular and is now on its way out...to be replaced with the scene kid. not that there's anything wrong with an emo kid, apart from the whole... i wan to die, wist cutting attitude. most of them are pretty sweet people. they mainly like cute depressing mainstream bands. they can be quite shy and prefer not to be in a big group.
they wear drainpipe jeans or a tutu. they wear converse in any colour they fancy,band t-shirts or tops from criminal damage etc. with a black hoodie. often, they will have a few badges on their hoodie, a wristband or happy coloured bracelets. they may have black hair that they dye themselves, a fringe covering one eye. the hair will be about shoulder length if not a bit shorter, often with a headband in it.
overall, emo kids are cute, but be nice to them, get them out of the whole wrist cutting thing. =)