If you use SMS, you should check out TeleFlip. They offer some cool free services that help combine SMS and email.

If you want to send SMS using email, you can do it using there service. Just send an email to teleflip.com with the persons 10-digit phone number as the recipient like so: 8005551212@teleflip.com. If you do this, your email message will be sent as an SMS to 800-555-1212. Pretty cool.

You can also sign up for an account on their site to get your incoming email messages converted to SMS that are then sent to you. The thing that makes this cool is that yo can create rules about which emails actually get converted and sent, so you only get the SMS versions of the emails that you really care about.