"From July 12 to October 12 '05, Sprint PCS subscribers will be able to send a text message to a landline phone. Text messages, which are converted to voice, can be sent to any landline phone in the United States. When the person answers his or her home phone, they will "hear" the text message you sent and can reply back to you with one of the available responses. You will also receive a text message on your Sprint PCS Phone when a response is sent back to you."
--via Engadget
