Good free opt-in email scripts

Hello there,

I've been messing around with the WEBinsta mailing list manager script all day and getting tired of it. Whatever the problem is it's the same one others have posted about on their forums with no response. I've installed it before and used it and liked it actually but...

Anyone know of any another good free/open source mailing list manager script(s)?

I'm wondering if im waisting my time if there's something out there that's better anyway.

Please post if you know any !

Thanks,

JT