just go check out the phpbb web site, it explains everything,
there is an artical on changing the header and footer,,,
lots of different mods/hacks
nuntsy is one of the best modders there, i use his scroll addition to the board works great!
ps: do you know php? if you do you can easily make your own costom header for a phpbb board.
Look at the bright side, if microsft didnt mess up so mutch most of us wouldnt have jobs lol