Like on Ubuntu (or other Linux distribution), If you look in usr/share/sounds  you'll be able to access all system's sound and customize them !

You will need root access (Download rootsh from app manager) and WinSCP (download winscp and connect to the phone via ftp through a wireless connection) to see system files and replace sounds in usr/share/sounds :

- camera_snd_title_1 (camera shutter sound)
- camera_snd_title_2 (video recording sound)
- camera_snd_title_3 (the focus sound)

All you have to do is to replace them with any working wav sound file  (Example)

For a silent camera, just rename or delete these files!

Via : talk.maemo