http://www.nintendoworldreport.com/news/28749

http://andriasang.com/comzfq/3ds_diary/

From Article:

"Nintendo Letter Box Available for Download this Week

Nintendo’s 3DS messaging app, Letter Box will be available in Europe for free starting Thursday, December 22.

Letter Box is Nintendo’s first messaging app on the 3DS. Reminiscent of a souped up PictoChat, it utilizes StreetPass and SpotPass functionality to allow users to share messages, drawings, and photos with their friends.

Although there is currently no information regarding its North American release, it's likely to be available this week under the name Swapnote. The software is already available in Japan under the name Itsu no Ma ni Kōkan Nikki. Videos from that version are embedded below."

Thats some sick shit right there.

UPDATE: Its available for download on e-shop right now.

@spurgeonryan Spotpassing allows instant messaging and Streetpassing allows you to put your friend code out around you so it's easier to play with people within your region. There also seems to be multiple wallpapaers you can put with your messages and you can add photos and sound clips to them. All in all, this is one of the best free applications I ever received from Nintendo (aside from Zelda Four Swords).

Looks amazing!

Edit the OP quite a bit. Replaced it with a better article. Its kinda like a Pictochat online and then some.

Wait, so you can message your friends?? That's cool.

Really DS should have had this

I'm ready!

No streetpass/Spotpass. You need on board memory for these things to work (pre- Dsi).

any normal messaging?... gueww it'll have to do fo now

This looks really good, especially for free. It's very Nintendo too, if anyone gets what I mean. I look forward to downloading. Now all I need are some friends to talk too.....