That is a good idea. I've seen it done before.
All of my addresses are on my computer...I already have the baby shower addresses grouped together, so just have to add/remove depending upon who gives a gift. Once that's done, just have to print them at home onto labels. ;)
I also already have my birth announcement addresses all set to be printed as they will be sent to all addresses I have. Just need to order the announcements once he's here.
Then we get our return address labels from vistaprint.com