I am looking for a mission trip for youth (doesn’t matter where, really). I am most interested in working with children. Also, could you include a website, if they have one?
I couldn’t find a fitting category, so, I just randomly selected one!

Acquire the Fire has mission trips every year.

http://www.teenmania.com/corporate/index.cfm

You could also check out this article (which is not, despite its title, against mission trips)

http://www.csm.org/articlewhymost.php

It is on the Center for Student Missions site, or CMS, but it doesn’t look like individuals can sign up – it is more for youth groups.

http://www.csm.org/index.php

You should definitely check with the youth pastor at your church. Or if you aren’t currently attending a church, look for one nearby with a youth group.

Also, there are probably limitless opportunities for ministry in your own or surrounding communities. Remember Matthew 25:31-40

http://www.biblegateway.com/passage/?search=Matthew%2025:31-40&version=31

Hungry, poor, broken, sick and imprisoned people are everywhere. And all of them need a friend who isn’t afraid to love them and show they care.