Does anyone know of a program that will extract all the e-mail addresses from a text file, even if its got loads of text and other stuff in between.

Basically, I want to save an item of junk mail as a text file, then run a program on it to get a list of e-mail addresses I can then use to send one back to every single one of them so that I can advise them not to send me any more junk mail...

The thing is... its got loads of To: From: and Cc: entries
as well as replies and forwards
Therefore, theres quite a few e-mail addresses, too many to extract manually.

Any suggestions?