The underlying melody is:

E||-------------------------------|
B||-------------------------------|
G||---4---4------0---0------------|  (listen to the song to figure out how and
D||-------------------------7---7-|   when to play each figure)
A||-2---2-------------------------|
E||------------3---3------5---5---|


The main melody is:


E||--------------------------------------------------------------------|
B||-7-10-9---7----5--------------------7--5----5-7-------8-7-5---------|
G||-----------------7----6-7-6-4---2-4-------7-----------------7-6-4-2-|
D||--------------------------------------------------------------------|
A||--------------------------------------------------------------------|
E||--------------------------------------------------------------------|


The later part:

E||------------------------------------------------------------------|
B||------------------------------------------------------------------|
G||--------------------------------6-----4-4-6---4-4-6-4-3-3-3-5-5-5-|
D||-4-4-6---4-4-6-4---4-4-6---4-4----7-------------------------------|
A||------------------------------------------------------------------|
E||------------------------------------------------------------------|

Then it goes the same as the main melody, without the (7-10-9) part and it's a whole 
step higher (so you'll want to play it two frets higher). The song loops at this part.