Mailfind is an easy to use application for extracting a list of email addresses from a wide variety of files, including those from your mail applications, text files, databases and more. Mailfind is better than most similar applications at spotting false positives, including partial email addresses, and temporary emails. You can review the results, quickly include or exclude emails, and edit the list of known domain extensions if you want to omit addresses from particular domains. And best of all: its free!
Mac OS X 10.4 or later