You need THIS adapter, then you can mount 58mm filters. (58mm is also the size of filters that fit the 18-55mm 'kit' lens)
ND stands for Neutral Density...they basically block some light so that you can use a longer shutter speed (or wider aperture) than you would be able to otherwise.
Do be so impatient...you could easily have found that information by searching Google or even the B&H site.
As I mentioned in the other thread you started...you don't need a macro lens because your camera will focus down to 1cm without any adapters....that's one thing that digi-cams do better than DSLR cameras.