If you use your Pocket PC device to do some or all or your email, you need to have a look at The Definitive Pocket PC Mail Client Roundup written by Menneisyys and posted over at Pocket PC Thoughts. As he writes, this is not a tutorial of each e-mail application (make some Google searches / look around on the developers’ homepages for simple tutorials / reviews). It’s a very thorough test and comparison with a lot of of practical usage tips.
Among the clients reviewed are the built-in Pocket Inbox and Messaging client, WebIS Mail, Qmail and others.