Sony once considered adding e-mail as an official feature for upcoming versions of the PSP's firmware. Well, it looks like the homebrew community (as usual) has beaten Sony to the punch. "PSPoste
is the first fully functional email application for the Sony PSP. It supports the SMTP and POP3 protocols (possible future IMAP support), and provides a skinnable user interface allowing the user to retrieve, compose and display messages from multiple email servers." It has a nice, clean interface, with a less frustrating keyboard method than what the PSP currently has. It still won't be the most comfortable e-mail application, but for people that are constantly on the go, this feature may be a life-saver.
[Via PSP Hacks