If you are using a GSM phone/device, there is a code you can use when sending SMS messages to confirm that they have been delivered to the recipient. All you need to do is precede the message with a series of three ones. Like so:

111You can tell if this message is delivered

The person getting the message will not see the 111 at the start of the message, that will be removed. Once their phone downloads the message, you'll get a confirmation message. You still can't tell if they have read the message, but you will know if they have gotten it.