The Nintendo 3DS utilizes a similar title-based organization as seen in the Wii and DSi platforms. The same update server is being used as was with the DSi, however a new common key has been introduced.
The organization of Title IDs has not been documented fully yet.
Here are some confirmed Title IDs (from the first update):
00040010-00024000 - Promotional video
00040010-00025000 - Promotional video
00040138-00000002 Home Menu