Many-a-times we feel that the email should not be sent right-away. Rather it be sent at the precise moment. A Birthday to be wished, an Invoice to be sent etc.
However, Gmail doesn’t offer this luxury. Not even in the now defunct “Labs”, is this vital tool included.
I have searched for the ability to schedule my emails & found that Google has taken note of this request many times (via Suggest a Feature) but done nothing about it except standard replies like: “While we don’t have this functionality today, its something we may add in the future and we’ll be sure to take in this feedback when we prioritize new features” Lame 
However, today I will provide not one but two ways how you can do it!
First up is an Online website:
LetterMeLater.com :
This website has been around for ages! It offers very simple online emailing option & the mail is sent from your own mail id i.e. yourname@anydomain.com
Instantly you will worry about security issues & how “anyone” could create the email alias & cause problems. But you need not worry.
As, at the time of registration itself, LetterMeLater sends an automated mail to the mail id being registered for confirmation. Thus, only the authorized user of the original email id can send mail through his / her email id on LetterMeLater.com
An added advantage of this site is, it is not limited to Gmail. Any domain name (office email ids also!) can work.
Next up is Boomerang for Gmail.
Strange name for a email add-on as Boomerang actually stands for a device which “comes back” after thrown!
This is basically a plugin for Firefox & Chrome (Sorry Opera, IE & other browsers’ users) which installs an “additional” button next to “Send” in Gmail wherein you can set a time & date as to when the mail has to be sent. Boomerang stores only headers of the mail on its servers & obliges your requests for the time/date. The boomerang team assures that emails are not stored on their server. Hence your privacy should be safe.
As a added benefit, you can also choose to hide emails from certin id / containing certain subjects to be viewed later! nifty.
Source: [Boomerang for Gmail], [LetterMeLatter.com]
