After 4 years, my 2008 Mac Pro just experienced a grey screen, then black screen failure with the ATI 2600XT graphics card ... the usual troubleshooting methods pointed to a hardware problem.
Using the info on TS3630 from the link above, I determined the card's serial number was among those affected. I went to the Apple store this weekend, and they swapped the bad card for a good replacement at no cost to me. So, as of Sept. 2012, they are still honoring the replacement program.
Be sure to bring a copy of the tech doc + all your pertinent system info (the store was not aware of the program until I showed them the document). Also, do check in advance whether they have the replacement in stock ... I was lucky that my local store did, otherwise, they have to order and you'll need top make a return trip as they will not ship the replacement card to you.
kudos to Apple for handling this so well after all this time!