I mailed my STD's out almost a year in advance. I wanted our guests to have time to plan and save to go to Mexico. I did the Boarding pass STD's with all the dates, travel agent info, passport infor, website info.
I plan on doing a more formal invitationa a couple of months before the wedding and sending out invites for our AHR at the same time.
Here is what I did for mine...
http://bestdestinationwedding.com/fo...stds-done.html