Does anyone know of a website that helps people find relatives?

[Tina]

In genealogy we research our ancestors not living people but sometimes you can find people on Facebook and MySpace[Even law enforcement gets lucky with these sites now and then]. If that fails try:
http://find.person.superpages.com/
http://www.anywho.com/
http://www.zabasearch.com/

If they own property or have recently sold property, some states property tax records are online and a few states have probate records online. You will be able to find little else online.

There are companies that specialize in background checks to screen potential employees for companies that could be helpful in locating someone or you could hire a private detective.[That might be above your means but one never knows.]