Here in America, births are usually announced to close friends and family through mailed birth announcements sent out a few weeks after the birth.
Of course the most immediate family are typically either present or told by phone right after the happy event, and then they spread the news to every person they can get to stop and listen [:D]
The birth is then typically announced publically through a published announcement in a newspaper, which may occur in the area the child is born in and the areas each parent is from and the area where each grandparent lives.
Public announcements can also be found in things like church bullatins, alumni newsletters, etc.
The newest trends in announcements here are internet web nursery's, which many times are hosted by the actual hospitals (plus there are other internet sites that host them), which include a picture of the baby and a guestbook for people to leave messages. The parents are given an address which they can give to people they want to see the site. We actually used it so people who lived far away could see a picutre of our son well before we actually got around to getting pics out. In hospitals that don't have this option (or kids that have more computer savy parents) may set up their own internet birth announcement and then email the address out on the happy event, or they will set up a pregnancy site where the post journals/diaries of the pregnancy and then an announcement is placed on it after the birth.
Personally, we contacted people by phone, had an internet page, and placed an announcement in my and my husband's hometown newspapers. We did not place an announcement in the newspaper where we actually live, We did not send out printed announcements and this was our routine for both kids.
Moderator - First Time Moms, Parents of Preemies
Missouri State Coordinator
Mommy to Alex and Mason