hey guys,
i have gotten fifa 2003 3 days ago. I am doing pretty good, but i just can not figure how to win a head hit agaist the computer. Any advise?

There's a Bug in the PC version of fifa2003 where there's really no consistent way of winning free headers (meaning when there isnt a computer near you), but you can win headers versus the computer merely by jabbing down on the "header" button while pressing the direction you want to head. It's also good to note that in some areas of the field you can always win a header vs the computer (off a goalie drop-kick for example), and other areas where you will almost never win a header...

Bottom line:

just keep pressing the header buton and you will get a feel for it :P