Adding a Username Field to account creation? Issues with Zen+phpBB

Right now during account creation username=email address... Which is okay EXCEPT that I use zen cart linked with phpBB.

My customers are posting with their usernames in my forum being an email address.. This could bring unwanted spam for them and they would think I am selling their information.

I try to search before I ask anything, and I am very sorry if it has been answered somewhere.

Is there a contribution out that deals with this?

I would not be able to deal with this as usernames would have to be checked against the phpBB usernames as well because a new account on Zen Cart = auto signup on phpBB, but users can register on phpBB alone as well..

Thanks for reading. This forum is amazing help. -Yuji