With our first we waited until the 12-week ultrasound to tell people. Before that I had only told a random person I met at work, but it felt nice to get it off my chest. This time around the dr is doing an ultrasound at 7 weeks (I'm not sure why he didn't last time), so if everything looks good we'll tell our parents and my SIL who is staying with us for a week in August. Otherwise the official announcement will be at 12 weeks.