One of my favorite wedsites, http://offbeatbride.com/, says Save-the dates (or STD's) are from "a simpler time" when STD stood for nothing more sinister then the price of postage.
We are currently working on ours, which is a little crazy since invites are coming up fast. Mum has graciously designed an evite for us, and we are also putting together a fun postcard (hopefully). We have heard so many cool ideas and have a lot of creative juices to let loose.
Let the first signs of awesome wedding shine!