hi, i have deleated bonjour from my setting on my xp system by acident, how do i re-install??

hi, i am crap on a p.c. i was getting load of casino pop ups all the time so i went on the programmes and cleared off a few things and in error i have removed the bonjour thinking i didnt need it only to realise that it is needed for the sharing on the i-tunes, how can i get it back on. many thanks. please help me.....