FlexMail 2006 released
FlexMail is a full fledged email client for your Pocket PC. It supports reading and replying to ActiveSynched email for basic operations or through its infinitely more powerful POP3/IMAP4 services to your email server. With support for industry standard SSL and SOCKS proxies, you can connect to almost any email provider including GMail!
With FlexMail's many options you can customize your email usage much more than any the Pocket PC Inbox allows. Receive your email via ActiveSync and respond via your POP3/IMAP4 SMTP account. Have FlexMail only hold the last 5 days of your IMAP folders. Create local folders and server folders. Synchronize by age, size, and synchronizations status.
The downside? Pocket Informant wants $19.95 for it.