1) Open the menu, and go to profiles.
2) Enter the general option, and click on personalise.
3) after that, several option appears.
4) some of them are ringing tone, ringing type, ringing volume, message alert tone, vibrating alert, etc.
5) Go to message alert tone and change the tone u want to listen when message is received.NOte :
Only wav or midi formats are accepted as ringing tone. MP3s are not accepted as ringing tones in NOKIA 6600. U need to install a software "mp3 as ringing tone" or "mp2wmaogg.codec" to make mp3 as ringing tone.
If u want that software, send me feedback or reply.
And I will deliver u as email in ur email id.