I stole this idea from Dave Marsh. In his "Book of Rock Lists," he had a section called "The Sincerest Form of Flattery" where he listed songs that sounded so much like they were sung by another artist, that they could be mistaken by another artist (for example, he thought "Crazy On You" by Heart sounded a lot like a Jefferson Starship song). Here's my list of some sound-alike songs: I've given you the song and the real artist, you tell me what other artist they sound like.
1. "Up in a Puff of Smoke," Polly Brown
2. "She Sells Sanctuary," The Cult
3. "Come And Get It," Badfinger
4. "Say It Isn't So," The Outfield
5. "Baby Love," Regina
6. "In The House Of Stone And Light," Martin Page
7. "Rock Me Gently," Andy Kim
8. "Sweetheart," Franke and the Knockouts
9. "One Toke Over The Line," Brewer and Shipley
10. "Dead Man's Curve," Jan and Dean
11. "Plush," Stone Temple Pilots
12. "Rescue Me," Fontella Bass
13. "Steal Away," Robbie Dupree
14. "It's Only Make Believe," Conway Twitty
15. "I Can Help," Billy Swan
16."Long Cool Woman in a Black Dress," The Hollies
17. "Wicked Game," Chris Isaak
Bonus: "The Road to Hell," Chris Rea
Super Bonus: "You Gave Me Love," Crown Heights Affair