One of my favorite resources for more contemporary and unique invitations and stationery is Minted. The company is unique because they carry independent stationery brands, known for their artistry, detailed printing, and superb papers.
Minted has a wonderful selection of baby announcements, shower and birthday invites, and personal stationery. You even have the option of printing return address labels on the envelopes to match the design inside and can have thank you notes printed too! Some of my favorite baby and child themed designs are featured below: