Flash photography is usually only allowed on "daylight" attractions. If the attraction is indoors, then you can bet that flash isn't allowed. Video taping (minus on-camera lighting) is usually allowed unless segments of the attraction are sensitive in nature (animation tour at MGM), or envolve copyright issues (Rock-n-Roller Coaster pre-show, movies). And, yes, you will see it posted before you enter the attraction and/or hear it from the CM in the pre-show.