Alright, I went through the tabs here in UG and none of them really makes sense. This is 
I decided to tab it myself. I don't tab much but I can usually tell when something is wrong.

This song's fairly easy, even for beginners like me. Only three chords are used. E, A 
D


Intro: A


Chorus:

A
Dont worry about a thing,
D                        A
cause every little thing gonna be all right.
A
Singin: dont worry about a thing,
D                        A
cause every little thing gonna be all right!

Verse:
A
Rise up this mornin,
E
Smiled with the risin sun,
A
Three little birds
D
Pitch by my doorstep
A
Singin sweet songs
E
Of melodies pure and true,
A                                       D
Sayin, (this is my message to you-ou-ou:)

Chorus:
A
Singin: dont worry bout a thing,
D                        A
cause every little thing gonna be all right.
A
Singin: dont worry (dont worry) bout a thing,
D                        A
cause every little thing gonna be all right!

Verse:

A
Rise up this mornin,
E
Smiled with the risin sun,
A
Three little birds
D
Pitch by my doorstep
A
Singin sweet songs
E
Of melodies pure and true,
A                                       D
Sayin, (this is my message to you-ou-ou:)

Chorus:

A
Singin: dont worry about a thing, worry about a thing, oh!
D                  A
Every little thing gonna be all right. dont worry!
A
Singin: dont worry about a thing - I wont worry!
D                        A
cause every little thing gonna be all right.

Outro:

A
Singin: dont worry about a thing,
D                        A
cause every little thing gonna be all right - I wont worry!
A
Singin: dont worry about a thing,
D                        A
cause every little thing gonna be all right.
A
Singin: dont worry about a thing, oh no!
D                        A
cause every little thing gonna be all right!

Have Fun!