Wow, really? That's got to be really helpful information for a lot of people; the Adobe web site just says "To install upgrade successfully, you will need a serial number and a previous version of this product on the same platform as this purchase." -- it would never occur to me to call them and ask for a different serial number!
Adobe Photoshop Elements 2.0 is worth a mention also -- at $99 it might be a good solution for folks who need a bit more power but not the full-blown Photoshop. I've been hearing good things about it.
Thanks for your post!