I find this idea is pretty awesome, you can actually send email to your future with FutureMe.Org. Here is the sample that I write to myself!
It is very simple, you just fill them out like a normal email, choose when you want to deliver and click "Send to The Future!". The private and public's setting is to set whether you want to share your letter to the public. To see public letters from others, you can navigate to "Read Public Letters" tab. You will see many delivered future letters here. After that (the final step), you just need to click on the verification link that send to your email.
Not necessary you must send to yourself, you can also send to others. To do that, you must register first and login. Once you login, the steps are similar but you can now choose who you want to send your email to. I think you also can send to multiple emails with ";" as separator.
When the time comes, you will receive an email something like this.
This is something I think can be improved because it doesn't look like an email. I did this last year (as you can see) but it may have changed now. Nevertheless, this is still a very cool idea! Try it out!
P/S: Not just merely for fun, you can use this as a reflection tool for yourself or maybe send a letter to someone who you have no guts to tell her/him something now! :)