This my first attempt here at BassMasta so I may be a little off, 
but hopefully you'll get the main idea.
After listening to the theme online, I began fiddling around 
on my bass in an attempt to figure it so I could cover it with my 
band.  The end result was what I found to be strikingly similar 
in sound to the actual theme song.  Well its pretty simple so learn 
and enjoy!

      
G:
D:
A:
E:00—9—8—00—9—7—00—9—8—7—3
                                   

                           When listening to the song, I associated the deeper sounds with 
the bass to make this riff.  I'm sure that the theme could be tabbed 
out in its entirety so as to be played on the bass, but that is for 
another time when I'm a bit more experienced; for those of you 
who feel up to the challenge, feel free to take a crack at it.