The Nintendo 3DS will gain a messaging service this week as Nintendo Letter Box is set to land on the eShop this Thursday.

Nintendo Letter Box is a free piece of software for 3DS that allows you to send messages, 2D / 3D drawings, photos, and sound effects to your buddies via StreetPass and SpotPass.

This interactive messaging service couldn't come at a better time, really, for it will encourage the creative among you to design your own digital Xmas cards and exchange them with your 3DS-toting mates.

The Nintendo Letter Box app will be available to download on Thursday, whether you're an Ambassador or not.