From GameBrew - a wiki dedicated to Video Game Homebrew.
VoiceAlarmClock is a DS homebrew alarm clock that allows you to record yown voice as alarm sound.
The archive contains 2 versions, each corresponds to a language (English and Spanish).
Copy the .nds of the language you are going to use next to the folder at the root of the flashcard.
At the time of recording it is recommended to speak loudly and clearly, and then turning the DS volume to full. Otherwise it may sound somewhat distorted.
To customize the background, just replace the files (in GIF format) with the ones in the folder that accompanies the .nds.
Stylus - Alarm settings
Microphone - Record message (during setup)
ITouch DS (firmware 3.2e)
M3 DS Real (firmware 4.3)
Super Card DSONEi (firmware 3.0)