The first thing you need is a VGA/TV scan converter. This one
from Focus Enhancments should do the trick.
Since the eMac has a non-standard VGA port, you will also need one of these
. It's a cable that converts the eMacs "squished" VGA port to a standard one.
If you get a session timeout error when clicking the Apple Store link, just go to store.apple.com
and search for "eMac" (without the quotes) in the upper right of the page.