From pdaBlast.com Sprint offers text messaging to landline phones
Sprint PCS is offering a preview of an upcoming service that they offer. From July 12, 2005 to October 12, 2005, Sprint PCS subscribers will be able to send a text message to a landline phone at standard domestic text messaging rates! They will use a text to speech technology to read the message to the person that answers the phone.
When the person answers the 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.
Because this is a limited time offer it does seem likely that Sprint will be charging for this service after the preview period.