death to tabs

[John Russell]

Ok, seriously, I don't ever want to see another tab as long as I
live.  I want _every__ tab I ever wrote converted to spaces right
now and I never want to have a tab show up when I hit the TAB key
again.  All spaces all the time.  

I found 
  (setq indent-tabs-mode nil)

for future tab annihilation but how can I convert a doc with tabs in
it to just spaces.  Thanks for the help.

John

PS sorry for the brusque tone.  Its just one of those last straw things.