Okay on the map crossfire (im newish to cod4 so sorry if my explaining is a bit dull) okay theres a building where the side has been blown off you can walk up the stairs to the first floor u will kno if its the right house because its near barbed wire in the road and on the first floor is a washing machine u will need a rpg launcher on the first floor there should be a chair jump on it then jump up to the wall then jump to the 2nd floor there should be a bit of debrey faceing up wards get to the top then go to the top of it then get out the rpg launcher then fire it downwards while jumping you should be on the buildings roof if not do it again by walking up the debrey and fireing once on top the roof to the left of u jump u should be flying walk a bit there should be a shop window and a metal bar where u can no longer walk jump on the metal bar then drop on to the fence/wall below and u will be outside the map btw u can use the glitch to get around the place flying hope this helped