iphone vibrating button loose 3G

When i switch my phone to vibrate using the vibrate switch, the phone goes back and forth between silent / normal. The phone starts vibrating, so there is no way i can leave the phone on silent, because it vibrates and sound still comes because phone thinks it is in normal mode, so i have to turn down the volume and turn off sound for text messaging or jsut turn the phone off.
Anyone else have these problems, if i take it to apple will i get it fixed? Ive had the phone since december but didnt take the apple care warranty, am i still covered?
My carrier is Fido.
iphone 2.1.1 Windows XP