OK, so now what? E-Mail is insecure because generally, it is transmitted and stored in plain text ... how can we circumvent that?
Easy!
Encryption! PGP (Pretty Good Privacy) is one top competitor that full integrates into Microsoft Exchange, Microsoft Outlook, Microsoft Outlook Express, Eudora, Entourage, Apple Mail and is available for most the MS Windows and Mac OS X platforms.
GnuPG, a less graphical however, full featured replacement for PGP is available for FreeBSD, OpenBSD, NetBSD, MS Windows 95 through XP and Mac OS X.
Another secure e-mail contender is HushMail... an easy to use encrypted web-based e-mail service. And if you are in to using packets and TCP connections for encryption *wink* then StegTunnel. Oh, and never forget about steganography.
Steganography is fun.