#The Problem:

#You want an itemized listing like:
#JIM    JONES    100 MAIN ST
#JOHN   SMITH    100 MAIN ST

#Instead of the usual count summary like:
#100 MAIN ST    2

#The Solution: 
SELECT firstname, lastname, list.address FROM list
INNER JOIN (SELECT address FROM list
GROUP BY address HAVING count(id) > 1) dup ON list.address = dup.address

http://stackoverflow.com/questions/854128/find-duplicate-records-in-mysql

duplicate record finder that itemizes results (vs. count summary)

MySQL