chocolatedrop, I plan on doing the same thing. We knew around December that we would definitely have a destination wedding and told anyone who asked. (For those we knew we weren't inviting, we told them it was going to be a small destination wedding but that we'd have a reception when we return.) We got engaged about a month ago and are getting married in October 2009. My goal is to have the invites out, complete w/booking info, at the end of the month. I've already emailed, texted or called my family and closest friends with the date. I don't want more than 40 people there, so if I start getting no's I'll have time to mail out the B-list invites without them knowing they were B-listers. So I guess my invite *IS* my STD.
My question is, how much time should I give them to RSVP? Is two months (July) enough time or way too long?