Ah jeez.
I went and googled a portion of the unencrypted text and found this site:
Solving Kryptos.
http://filebox.vt.edu/users/batman/kryptos.html
Whaddaya know.
Palimpsest IS a key. It's also a word for something altered yet bearing traces of its original form.
KRYPTOSABCDEFGHIJLMNQUVWXZ
1
PTOSABCDEFGHIJLMNQUVWXZKRY
2
ABCDEFGHIJLMNQUVWXZKRYPTOS
3
LMNQUVWXZKRYPTOSABCDEFGHIJ
4
IJLMNQUVWXZKRYPTOSABCDEFGH
5
MNQUVWXZKRYPTOSABCDEFGHIJL
6
PTOSABCDEFGHIJLMNQUVWXZKRY
7
SABCDEFGHIJLMNQUVWXZKRYPTO
8
EFGHIJLMNQUVWXZKRYPTOSABCD
9
SABCDEFGHIJLMNQUVWXZKRYPTO
10
TOSABCDEFGHIJLMNQUVWXZKRYP