Future Me - Send an email to your future self
HEY - Email at its best, new from Basecamp.
Dabble Me - Your own private place to write. A journal/diary to help you remember what's happened in your life.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
Letter to my future self - Letter to my future self is a prominent email scheduling service that gives you the opportunity to create a letter with goals and thoughts for your future self and schedule a date for sending it.
InstAddr - Disposable email address application.