Steve: You need a mailing list, not a mail application. The easiest one is LetterRip, but I'm not sure what the status is of that product (I have a license for a Mac OS 9 version, and I don't think a Mac OS X version is even under development). However, you need to look at that type of software, not PowerMail as your solution. There are a bunch of things out there : See http://mac.sofotex.com/Email_Utilities/Mailing_Lists/ For a list of software that will fit the bill.
Wayne
