Hushmail: Free email with encryption.
mail.com: Also has "email.com", "@post.com" and a variety of other addresses.
Yahoo: Yahoo has many other facilities including the Yahoo directory, Yahoo groups and search engine.
Lycos: Another free email service.
Hotmail: Popular site for email. Owned by Microsoft.
Forthcoming:
Google announced in March 2004 that they will be offering web-based email soon.
8 Apr 2004