Standard E Tuning (eBGDAE)
Effects used: Delay, on intro.

The main riff goes as follows:

E|------------------------------------------|---------------------------------|
B|------------------------------------------|---------------------------------|
G|------------------------------------------|---------------------------------|
D|------------------------------------------|---------------------------------|
A|-----11-11------11-11------11-11-11b12p11-|-----9-9-----9-9-----9-9-----9--9|
E|-0-0-------0-0--------0-0-----------------|-7-7-----7-7-----7-7-----7-7-----|

|------------------------------------|
|------------------------------------|
|------------------------------------|
|------------------------------------|
|-----7-7-----7-7-----7-7-----7-7----|
|-5-5-----5-5-----5-5-----5-5--------|


And that's the only riff in the song! The rest of the song goes Emaj, Bmaj, C#min, Amaj. 
Easy riff to play and sing along to.