adding intro page(skip adv) with cookies to index file

hello ihave site [login to view URL] ineed to create page with flash adv ( intro page) thats start before my site open and play flash advertise there will be a SKIP button ( if user press on skip it cookies will save that and not showen the intro page next time in the coming 15 minutes ) also adv will skip automatecly within 15 second .. n.b its need to be in the same page not a lot rediredting page ..