It's interesting that I finally find my own solution to get this working in zencart, and you post today about updates tomorrow.
I may try your update as I do have other sites to place phplist on, but I grew frustrated long ago about no updates. Either or, it's strange, I got everything to work properly on one site back in January, and for the life of me have never gotten it to work on any other site. Pure Luck I gather.
Anyway, my solution to integrating phplist into zencart is this:
Install phplist, be sure the setup is working, create your list(s), and your subscribe pages.
Make a trial run, install a subscriber to be sure it's working properly.
Next,
Go to Zencart admin,
Tools | Ezpages
Create an ezpage for the newsletter, I named mine Newsletter Central.
I placed the code for an iframe into the description box as this:
<p align="center">
<iframe id="ifrm" name="ifrm" src="http://www.myurl.com/pathto/lists//?p=subscribe" scrolling="no" width="450" height="400" frameborder="0"></iframe></p>
(change myurl.com to your url and pathto to your path)
It will then load all phplist pages into the iframe when clicked on. I created my own custom subscribe page according to phplists documentation on how to create a custom subscribe page, so my iframe looks like:
<p align="center">
<iframe id="ifrm" name="ifrm" src="http://www.myurl.com/lists/subscribe.htm" scrolling="no" width="450" height="400" frameborder="0"></iframe></p>
This makes phplist look better than it's bland subscribe/unsub/ and preferences pages.
It also adds a link to your "header, footer, sidebox" or wherever you tell it to on the ezpages areas.
My reasons for using an iframe were because without it, when it takes you to the thank you page, or unsub pages, or even the preference page, there is no way I have found to customize these by themselves, so placing them in a iframe keeps the colors and design of site in place, with them out of the iframe it does not do that.
Please note, I have no solution to make confirm emails work, but this gets past the problem of having the page bounce back when the signup that doesn't work goes back to the subscribe page. If you can live with the customer not confirming the subscribe, phplist will work fine otherwise.
Marian