If you have a US T-Mobile To Go Pay as you go phone you can receive free text messages. Big deal. But what is nice is that you can send text messages by email by sending the message to firstname.lastname@example.org, where x is the number of the phone. To send me or Catherine a message send email to 3106898871--at--tmomail.net.
Going the other way you can use sms2email. This is a UK number so check your text message prices. To send an email from a phone text to +447766404142 as follows:
graham--at--grahamdavies.net message after the address.
Of course switching the --at-- for an @ symbol. How exciting...