On all calls (Wi-Fi, 3G, Skype-to-Skype, Skype-to-Phone) I can't hear anything coming out from my iPhone call speaker (where calls are generally made out of) at all. When I change it to the phone speakers (the ones from where the music comes out, ...) I can hear the call perfectly.
I am running iOS5, iPhone 4 and the latest Skype build.
This problem just began with my iphone 4s. It was working fine and now I can only hear on headphones or speakerphone but not on internal speaker. I tried uninstalling and reinstalling. I keep having problems with this iphone and it has already been replaced once by Apple.
Just to add that I have the exact same problem on my iPhone 4s. It appears to be ringing and I think most callers here me but I get nothing unless I enable to loudspeaker. This has also been the same with different versions and after reinstalling.
Skype... come on
This may sound a little bit silly, but have you tried turning up the volume all the way?
Also, make sure the mute slider on the side of the phone is set to unmute.
Can you hear anything if you put it to your ear?