Mail Scheduler Pro is the ultimate utility to send delayed and repeated messages.
A couple of the major features are:

• Send simple messages by entering the subject, email addresses en text.
• Turns any RSS feed into an email.
• Use your standard email application to create complex messages. Even html messages and attachments.
• Fetch a web page and send it as an email. Great if you have a blog or online price list.
• Send messages once. Want to send a message a year from now? No problem! Just add it to Mail Scheduler Pro, set the date and forget about it. Never forget a birthday email again!
• Send messages every year, every month, every day or even every hour.
• Progressive schedule: Send a message each xx days and slowly decrease the interval time down to every hour. This is the perfect way to make sure you’ll get an answer!
• Runs in the background.
• Turn a web page into an email. Once or every time the message is send.
• Send an email (with attachment) when a file changes.
• Send an email (with attachments) when the content of a folder changes (even compresses subfolders first). Great way to create your personal dropbox.
• Get notified through Notification Center or Growl!
• Works great with GMail and many other email providers.
• Much more…..