there are two possible solutions:

1.

go to settings and find the audio thing, then set it to vibrate.( i've never seen your phone so I'm just guessing)

2. download a silent ringtone - I dunno any sites, but I do know they're out there.

i just got my first phone, and it's a nokia 6010, i'm trying to set the ring and whatever message alert on vibrate-i'm not having much luck. i don't like cell phones ringing, and i especially want mine as quiet as possible. thank you!