Yourli.st is a free email reminder service. No need to register. Just put in the event you want to be reminded of, when you want to receive the reminder and the email address to receive the alert. You can even have the reminders sent to your blackberry. Use it for yourself or your clients.
There is even a bookmarklet you can add to your toolbar.
I tested it and it worked fine. Here’s the alert screen:
This is a great tool, I use it all the time.