is there a way to find a persons yahoo e-mail address? Is there some type of directory for yahoo addresses>

Answer 1

Sure you can if they have elected to have the e-mail address public, go to the link for their profile.

Under the heading "find people on Yahoo!"
Click on the drop-down menu
Choose the "Yahoo ID" option
Enter the user ID into the search box
Click "search now" and you're all set.

Answer 2

AFAIK, there is no such thing