There are a number of spots where people can "check in" so others can find them.

The Red Cross added one yesterday afternoon called Family Links.

You can go to www.redcross.org and click on Family Links on the right.

The direct url is http://www.familylinks.icrc.org/katrina

There is also an 800# where you can call in and have someone at ACR register you in the database or do a search for you.  Call 1-877 LOVED-1S  (1-877-568-3317)