Jott.com provides an interesting service for iPhone (or any mobile) phone users. The free service allows you to dictate short messages to yourself or to others over your mobile phone.
The intent is to provide a way for people "on the go" to send themselves and others short text messages just by using your voice. A toll free number is provided which identifies you based on your mobile phone caller id. You are prompted for who you'd like to "Jott" to and you then record your message. The message is then transcribed (by humans) and sent to the recipient.
When you receive the message, a link to the audio is also provided (sample) in case the transcription is somehow missed.
Mashable reports that Jott is venture capital funded and plans to keep the basic service free.