I have one Smart Key left from my 2007 Prius that was totaled last May. I tried to have the dealer reprogram it for my 2008 replacement Prius. They said it would only work in a 2007 and could not be used in my 2008. If anyone is interested in it, let me know. Since I apparently can not use it, I hate to see it go to waste.
Tempe Toyota is the real master on the smart key, you may want to double check with them. They reprogrammed one for me I got on ebay in 5 min, and did it for free. Mine turned out to be a dumb key and he showed me how the silver toyota emblem is the way to tell a smart key from just a plug it in key.