Some clever folks over on the UK board have figured out how to retrieve existing ADRs online!
On
http://www.disneyworld.com hover over "my Disney vacation" until the menu pops up, then click "dining reservations" at the bottom of the menu. Then just enter the confirmation # for a particular ressie and the phone number you provided when making it. The phone number should be in the "xxx-xxx-xxxx" format, including dashes.
Tadaaaah!

There's your confirmation!
I've only been able to retrieve about half of mine, which I fear might be due to a phone number mismatch or something along those lines.

I do remember the CM taking down 6 ressies and confirming those before proceeding with the next batch. It seems that I can only retrieve the first batch now.