[david_shaw]

Most (if not all) cell providers that allow SMS to other phones will also allow SMS to e-mail addresses. Back in the day I wrote a news/movies app (before Google released their GOOG SMS service) that received an email with a query, parsed through the mail spool and sent off a reply. Worked pretty well.

[Attocs]

The people sending the sms messages are very poor and will have the simplest phones on the market, I have one of these such phones and it doesn't seem to be able to send sms to email.