A 3D Glasses effect really shouldn't be that difficult. All you need to do is set up two different cameras and position them next to each other. Give one a green tint and the other a red tint and overlay them. This works because the two cameras are positioned just like your eyes are, so they would act the same way, getting slightly different angles of objects and returning the illusion of three dimensions.

When your script isn't working right, usually it's because it's doing exactly what you told it to. -An Unknown Programmer