No one seems to have got this completely right yet so I thought I might have a go at tabbing the whole thing with all of the guitars in.

Tuning: DADGBe

Intro

Guitar 1 (clean)
E|---------------------------
B|-----12--10-----------10/12
G|-999 -------12-999-12------  Repeat until the verse starts.

Guitar 2 (clean) - This comes in after guitar 1 has repeated the above riff twice.

E|--------3--2---
B|--------------3
G|--------0--0--0
D|-2-2-2--------- Repeated until the verse starts.

Guitar (clean with a tiny bit of phazer) 3 This comes in after guitar 2 has repeated the above riff twice.

E|-5/3-3p0
B|-5/3-3p0

Verse

Guitar 1 (acoustic sound)People have put several versions of this bit but I think this sounds the closest.

E|---------------------------- 
B|---3-3------3-3-------3-3---
G|--0---0-0--0---0-0--0----0-0
D|-0-----0--------------------
A|----------2-----2-----------
D|-------------------0------0- Plays through whole verse

Guitar 2 (light distortion) Starts as he sings "and we all sit round"

D|-4-----5----7
A|-2-----5----5
D|-------5----- X2

D|-44444444-55555555-00000000
A|-22222222-55555555-00000000
D|----------55555555-00000000
  Palm mute, slowly release

Chorus (heavier distortion)

D|-00000000-44444444-55555555
A|-00000000-22222222-33333333
D|-00000000------------------   X4

Then the guitars go back to the beginning once and in the same order,
until it goes back to the chorus again.

After the chorus guitar 1 does the intro riff once then the solo comes in,

E|------------------15-14----
B|-15151515---------------15-
G|---------14-12-12----------  X3

E|-15-14-----15-14----17-14----19-14---
B|-------15--------15-------15-------15
G|-------------------------------------

E|-------------------15-14---
B|-15151515----------------15
G|----------14-12-12---------  X2

E|--------------------------------------------
B|--------------------------------------------
G|-19^21-19^21-19^21-19^21---14^16-14^16-14^16

The beginning solo riff is then carried on into the chorus.I think it plays 
through until the end.
If you have any comments/correcions email :samspudley@ntlworld.com :)