Free Email - Searchable directory guide of free email providers with reviews.

zWallet - Get paid to use email!!!  Also get paid for referrals.  Web-based.

Hotmail - One of the most popular free email providers.  Web-based.

EmailAddresses - Search over 600 Email providers.

Free Email Providers Guide - Select up to 22 features & search over 1,200 Email providers.

Outblaze - Add web-based e-mail, scheduling/calendar, message boards, greeting cards, and your own chat room services to your website for free.