I like hushmail/elite b/c I've read through the source code and like what I see (its avail on their site - ai.hushmail.com or maybe it is hushmail.ai - something like that).
careful though, it is only secure to other hushmail users, or users that have an address that is licesnse out under their system - such as elitefitness. if you are e-mailing from there to an aol one, or vice versa, it is plain text and not secure.