Save the Dates.  Generally these are sent about 5-6 months ahead of time (for a non destination wedding).  You're welcome to get as creative as you'd like, but don't forget to say where the wedding will be (common mistake).  These aren't 100% necessary, but make a nice touch.  If you're looking to save money you can always send them via email (with a nice layout).  www.daxphotography.com