We've been working hard on our documentation lately. The first priority has been to make new email client setup and user guides. Everything now on the Setup email client page is new and improved.
Resellers should like this because the PDF's can be edited with Adobe's PDF software or even with 3rd party PDF editors. So minor rebranding should be very easy to accomplish: swap a logo out, change a Webmail reference, etc. These are released under a Creative Commons license that allows reproduction and changes so long as we get attribution and there isn't a charge for the documentation (because we don't charge for it).
These are short, clean, and simple guides to set up and use email clients with our service. Here is the list of docs on the site right now:
Outlook (2003, 2002/XP, 2000, 98)
We're working on more docs right now; Versamail comes to mind. Our service runs fine on Versamail (I'm using it on my Verizon Treo 650) and nearly all mobile email clients. As long as the program supports POP or IMAP and can do SMTP Authentication with our servers it should work.