Duplicates in ITunes?

Hello all. I have had a terrible job trying to get my ITunes library back into order lately. There were songs missing from albums and a lot of stuff seemed wrong in it. I am slowly putting it together again, but now find I have a lot of duplicates of my songs. Is there a good duplicates remover anywhere that I can use? Short of this, is there any way I can remove the duplicates a little easier than one at a time?
Thank you all.
Kirstan.