there is a number floating around on the theme parks board...don't recall where exactly but maybe search will bring it up.
I tried it last year because I had some old park hoppers I didn't know how many days were left. For most of my phone calls,they told me they can not check over the phone...I kept calling and finally got someone that said she would check to see if they were expired, but would be able to tell me how many days were left. She said they were expired. I brought them with me to Disney anyway and had them check at guest services, and they weren't expired at all. In fact they each had 2 days left on them. I guess the girl just told me they were expried so I'd stop calling, lol!