This is the main part and not the sort of chorus, HitchHiker's Guide bit.

E---------------------------------------------|
B---6-4-3-1----6-4-3-1----6-4-3-1-----6-4-8-6-|
G-5----------3----------2----------1----------|
D---------------------------------------------|
A---------------------------------------------|
E---------------------------------------------|

The HitchHiker's Guide movie-version has a variation on the 6-4-3-1 bit which goes like this--

E----------------|
B---6-4--1H3-4P1-|
G-5--------------|
D----------------|
A----------------|
E----------------|

And then a variation on the 5-3-2-1 which goes like this --

E--------------------|
B-----4----6-4-3-1---|
G-3H5--3H5-----------|
D--------------------|
A--------------------|
E--------------------|

The strumming bit is muted in parts but is basically Am, Am7, D7, F6, played with the 
on the 3rd fret (Cm, Cm7, etc...)

So, that's about it. This is my first tab. Thanks.