Kind of in the middle, towards West Side. I'd park in West Side parking lot, but go down towards Pleasure Island. The theatre is really quite large and there's two entrances. One near PI and one closer toward DisneyQuest. I'm not positive, but I think there's DQ, then a couple shops and Virgin Records and then the theatre. I'm sure you could also take the PI entrance too and park there.
We went to a couple movies in December. DH has off that week in May and kept trying to "talk" me into going down to see Star Wars at Disney for my birthday!!! I'm gritting my teeth and trying to save money. As awesome as that does sound.