Ghost-type moves had no effect on Psychic Pokemon. This was actually a mistake: several game guides stated that Ghost was super-effective on Psychic, and an in-game trainer at Saffron City says that Psychic Pokemon fear only ghosts and bugs! However, this only affected one move: Lick. The two other Ghost moves, Confuse Ray and Night Shade, affected all Pokemon equally. It was corrected in Generation II when Ghost became super-effective against Psychic.
Bug was super-effective on Poison and vice-versa. This was changed so that Bug is now not very effective against Poison, and Poison now does regular damage against Bug.
Bug was regularly effective against Ghost. Now it is not very effective.
Ice type moves were regularly effective against Fire type Pokemon. Now they are not very effective.
Source: This site's Type Chart. ( http://pokemondb.net/type )