Congratulations! 
Personally, I wanted to wait until 12 weeks - we had 2 early, suspected MCs and I didn't want to tell anyone just in case.
DH persuaded me to tell our parents and siblings at 7 weeks - basically because, if anything went wrong, he felt that we would need a bit of support (or, at the very minimum, to just be left alone if that is what we wanted).
I'm now 32/40, and tbh I'm still in 2 minds about whether it was the right thing to do or not. As soon as my mum and DSis knew they had their hands all over my tum which irritated the fuck out of me (couldn't feel a baby - just my fat
) But then, we had to tell them sometime!
Other than family/close friends we've not broadcast anything - nothing on FB, not informed distant relatives (although I'm sure word has spread through the grapevine) - we've maybe only told a dozen or so people. I'm a bit nervous about saying anything to anyone until he/she arrives, and I'm feeling so antisocial at the moment that I don't particularly want to be in contact with the world and his wife.
But - horses for courses! Just tell people when you feel comfortable doing so - there is no right or wrong!