APM: Open Source Listservs

[Goldilox]

I am needing to set up a mailing list that only mails out once a month, and
does not receive replies (but watches for bounces), starting with a few hundred
subscribers and moving on to a few thousand subscribers over time.

I saw a discussion here about Majordomo being a little unwieldy in its setup
overhead and some folks were talking about Perl based packages (open source).

Question 1:
Are there any recommendations for (or against) open source (i.e. free) mail
subscription packages?

Question 2:
Also, how powerful a machine would I need to run this kind of mailserver (I'm
hoping I can revive an old Pentium machine since it is just a send without
replies or discussion)?

Thanks for any help

Rhett