Yahoo's Buzz Log notes the top 20 most misspelled terms in Search. Here they are (correct spelling in parentheses):

1. Wallmart (Wal-Mart)
2. Rachel Ray (Rachael Ray)
3. Amtrack (Amtrak)
4. Hillary Duff (Hilary Duff)
5. Katherine McPhee (Katharine McPhee)
6. Britany Spears (Britney Spears)
7. Geneology (Genealogy)
8. Jaime Pressley (Jaime Pressly)
9. Volkswagon (Volkswagen)
10. Wikepedia (Wikipedia)
11. William Sonoma (Williams-Sonoma)
12. Tatoo (Tattoo)
13. Travelosity (Travelocity)
14. Elliot Yamin (Elliott Yamin)
15. Kiera Knightley (Keira Knightley)
16. Kelly Pickler (Kellie Pickler)
17. Brittney Spears (Britney Spears)
18. Avril Lavinge (Avril Lavigne)
19. Rianna (Rihanna)
20. Jordan Sparks (Jordin Sparks)

Obviously, some of these will be short-lived (Jordin Sparks, for example), and not all of them will be useful to your search campaign. Ok, none of them will be useful to most of our search campaigns. However, if any of those phrases are ones that you can make use of, go get 'em, SEOs!