http://en.wikipedia.org/wiki/Atomic_Rooster

You can play the main riff 2 ways; 1-On the E + A or 2-The harmony on the D + G. It
like John Du Cann played it on the E then over dubbed the harmony (or visa versa). I usually
it on the E (mainly because Cann uses vibrato on the string, not essential but if you 
to sound 'truer' tot the original) but on the last run through to give it a bit of
I play the power chord.

Main Riff (E + A) (I'll upload the intro later):

E------------------------------------------¦
B------------------------------------------¦
G------------------------------------------¦
D------------------------------------------¦
A-----------3--5-----3---------------------¦
E---5---5----------------5--3--5---3-------¦

and on the D + A...

E------------------------------------------¦
B------------------------------------------¦
G-----------5--7-----5---------------------¦
D---7---7----------------7--5--7---5-------¦
A------------------------------------------¦
E------------------------------------------¦

This next part is really easy too, its just a basic strumming technique which is easy
to work out when you listen to the track, so I'll just put the notes/chords to play. As
the 'main riff', the E + D are hamronised, but no vibrato is used here so you can play 
like a power chord but muting out the A:

E------------------------------------------¦
B------------------------------------------¦
G------------------------------------------¦
D--7--6--5--4------------------------------¦
A--x--x--x--x------------------------------¦
E--5--4--3--2------------------------------¦

I'll upload the rest of the song later :)