This song is more difficult than a basic riff, but once you get it down, it's a lot of 
fun to play.  Gotta love the Cold War Kids.

intro/verse:
E|----------------|----------------|
A|0---------------|----------------|
D|--2-------------|2---2-0-------2-| x18
G|----0-2---------|--4-------2-0---|

You continue with this riff through the first verse, through the instrumental split, 
through the second verse and then cut to this for the instrumental bridge.

Bridge:
E|3-3-3-3---------|----------------|
A|----------------|2-2-2-0---------|
D|----------------|----------------|  x2
G|----------------|----------------|

Then back to the main riff through the next verse and into the chorus line

E|----------------|----------------|
A|0---------------|----------------|
D|--2-------------|2---2-0-------2-| x12
G|----0-2---------|--4-------2-0---|

Then you have the same bridge piece, but there are words over it too.

Bridge:           "Will you take care of me?"
E|3-3-3-3---------|----------------|3-3-3-3---------|----------------|
A|----------------|2-2-2-0---------|----------------|2-2-2-----------|
D|----------------|----------------|----------------|------0---------| x2
G|----------------|----------------|----------------|----------------|

Then main riff from "While I am Away" to the end

E|----------------|----------------|
A|0---------------|----------------|
D|--2-------------|2---2-0-------2-| x22
G|----0-2---------|--4-------2-0---|

This is my first tab, so I hope it works on your bass!