I’m happy to report a PHP counterpart to imap2soap is coming in CiviCRM 2.2, so the handling of CiviMail’s return channel should be much easier in the future (ideally as simple as setting up a cronjob).
There are also other CiviMail improvements and changes in 2.2 (kudos to U.S. PIRG for their sponsorship!) which I plan to unveil in upcoming post(s), but let’s concentrate on the return channel for now.
The solution will be based on UI-configurable mail sources, and the idea is that every now-and-then – depending on your cron settings – the CiviMail processor will poll the source and take care of all the emails found there, either by processing them or ignoring. The processing will be done by using local API calls, so will also work on PHP installs lacking the SOAP support.
In the case of IMAP accounts, the emails from Inbox will be moved to either CiviMail.processed or CiviMail.ignored folders. In the case of POP accounts and local Maildirs, the emails from the account/dir will be moved to you CiviCRM’s
For the adventurous CiviMail users who would like to try this solution on their CiviCRM 2.1 installs, please contact me in this forum thread – but do keep in mind that this will require editing some files (as there’s no UI for the account configuration yet).