Shipping work flow

[hawaii350]

I'm just wondering how those of you that use prestashop handle shipping (primarily those of you that use USPS) Currently I use a site that is order by email and when I get an order I just fill out all the info using paypals multi order shipping. Of course order by email and having to fill in all their info is not efficient at all so I am switching to a real store (prestashop) I'd like to use endicia since they allow you to print RMA labels. Has anyone come up with a efficient system to quickly transfer order data to endicia or any other shipping service? I'd love to avoid reinventing the wheel.

Thanks!