From Beyond by Sleep
From the album Sleep's Holy Mountain
Tuning Drop C (C, F, A#, D#)
Awesome song, very heavy. You may want to consider adding "mini-solo" sections (when the 
sustains a note), has the bassist for Sleep does.
This tab may not be perfectly right, but I hope it gives you a good footing for the song.

First Riff(s)-
D#|--------------------------------------------------------------|
A#|------------------------5-------------------------------------|
F |-----7~---7~---7-7--------7------7----7----7--7------5--7-----|
C |---0----0----0------7-7--------0----0----0------7--7----------|

Second Riff
D#|-----------------------------|
A#|-----------------------------|
F |--7-7-7----7-7-7-------------|
C |--------6--------7-6---------|

Third Riff
D#|----------------------------------|
A#|--------------------------7-5-----|
F |-5-7-7-7-7-7-7-7-7-7-7-7------7-5-|
C |----------------------------------|

Fourth Riff (your may want to play this an octave lower for more heaviness)
D#|-----------------------------|
A#|-----------------------------|
F |-----8-7-5------8-7-8-7-5----|
C |--7--------7-7---------------|

Fifth Riff (your may want to play this an octave lower for more heaviness, esp. 
during the loud parts)
D#|------7~--7-5---5-7-7--------7~---7-5---5--------|
A#|--------------7-----------------------7---5-5----|
F |-7-7--------------------7-7----------------------|
C |-------------------------------------------------|

You're on your own for the solo section (just improvise)