Yes, you need to use a app like Astro and go into /system/media/audio/ringtones, copy them to your sd card then transfer it to your computer then to your Droid's sd card in a folder called media or ringtones. It would be easier to search for a system dump from the Eris and grab them out of there.

 

The Eris does have some sweet ring tones. My girlfriend has one and the ringtone she uses blows all of mine away.