Know Who Is Getting the Announcement
Some might balk at sharing baby pictures on Facebook, but it's truly the fastest way to share news and saves you the trouble of worrying about any etiquette surrounding who finds out first. If, however, you do want to send word to a VIP list of sorts, map that out ahead of time.
Consider preparing an email draft with the addresses already added in the "To" field a few weeks before your due date. This way, you don't have to wonder if you've forgotten anyone . . . or go digging around for your uncle's Hotmail account.