Here's a great website (www.jott.com) that will allow you to dictate memos from your cell phone (by dialing a 1-877-... number). The process is ENTIRELY free, very simple, and takes about 90 seconds to set-up. From my tests, it even does a great job at dictation. You essentially call the number, dictate your message, hang-up, and the message is emailed to your preset email address within minutes. It is really that easy.
The only down side is that each dication is limited to 15 seconds (altough you can dicatate several messages back-to-back without any trouble). The email with the dictation also includes a link to the audio file of the dicatation. Its a great way to send yourself a quick memo at the office, or any other use that you can think of.
For instance, I will have an email in my inbox tomorrow morning that reads: "note to self, don't forget to write your article for the March Precedent. It is due no later than TODAY!"