Nintendo has released a new Facebook application for the DSi.
To get it, you need to access the System Settings menu and download firmware version 1.4. A Facebook logo will then show up in the album section and above pictures. Tapping it will upload images to your Facebook account.
Up to 200 photos can be uploaded to your first album, which will be automatically titled "Photos from Nintendo DSi". Once you exceed that total a new album will be created.
Naturally you can muck about with the DSi's image-altering tools before you upload your pictures, and use the stylus to the write the word "SPAM" on your friends' foreheads and draw nobs underneath their chins. Maybe not the last two.