There are a lot of great songs for haiti found in youtube and these are some of my fave

Linkin' Park = Not Alone : [youtube]GwTWyWvYEig[/youtube]

Hoobastank = We are one : [youtube]TsL3-I6T[/youtube]

We are the World 25 for Haiti:[youtube]Glny4jSciVI[/youtube]