I have to say, I am almost 6 weeks pregnant, and pretty much everyone in my life knows about this. LOL, We, too, had plans of waiting a while to tell everyone, but the excitement kicked in and it was just too hard. I told my parents over the weekend and they were elated... dh also told his mom (who will be a first time Grandma) and she was very excited too. The fact that they are all so excited really does help with the nervouness of pregnancy. I also have been feeling a little scared about being pregnant, but each day my excitement grows and that is over powering the nervousness.
Anyway, like the other girls said, I would tell people when you are ready. I decided to tell my boss immediately incase she was wondering why I was running to the bathroom every 10 minutes... LOL and also I wanted her to be able to prepare for all of the time off I will need for appointments and such.
Good luck though... I am sure whenever you tell them will be perfect!