There are quite a few topics on this and a huge demand for this but I've been searching for weeks and it doesn't seem that anyone has come up with a successful solution. I've not even found a formal request posted for a mod that does this.
What we would like to see is ZenCart integrate with phpbb3. Currently ZenCart version 1.3.8a has an option to provide linkage with phpbb but it does not function correctly with phpbb 3.0.0. It does however function with phpbb2 versions.
The ideal solution would be when a user registers an account with either system (Zen or phpBB) that the registration information would be carried over to the other database as well. Basically I'd like to have a community forum that members have the ability to purchase items without creating another account in the shopping cart system. This could also work the other way too. When a user creates an account within the Zen shopping cart system the account information would be carried over to the phpBB system.
It seems that ZenCart 1.3.8a already has this ability this, it just has not been brought current to work with the latest version of phpBB 3.0.1. (Yes, I'm posting this MOD request at ZenCart's forum as well). So from the other end... I would like to see a MOD that sends the phpbb registration information over to ZenCart's database. Anyone?