Email send options to set a future delivery date

Unfortunately there is no way to do this in Gmail.

If you have Outlook 2007 available create a new mail and click on the Options tab. There should be a button in the More Options group called Delay Delivery. Clicking that will allows you to choose when your mail is sent. Outlook has to be running at your selected time, so don't just close it and forget about it! This option may be available in earlier versions, but I don't have them installed so I can't check to see where they are

If you don't have access to Outlook, Thunderbird can do this, just go to File > Send Later (or press Ctrl + Shift + Enter)

If you must use a web-based program, you can use something like FutureMail, though I would test them first to make sure you're not going to be sending ad-filled email which looks like it's being sent from a strange email address.

If all else fails there is always the manual way - write the email, save it in your drafts, and then when it's time to send it, manually do so.

Inbox hit shift click on the emails you want to send hit forward. This allows you to join emails that are not related to each other.