I'm guessing this is a probably an Optus Network issue rather than an iPhone thing - but at 9:20am and at 10:20am my iPhone's received an incoming call...from its own number. When I answer its just a garbled, underwatery mess of hellish noise. Kind of like when you get too close to a hell-portal in Doom 3.

Anybody else had this?

Keep in mind that that nobody knows this number as I've only provisioned it while I wait for it to be unlocked.

Most people got a call from their own number when the phones were first set up. This was an automated Optus call to set up voicemail. Don't know why your calls are just a noise though.

i've had the garbled warped sound a bit on calls on my iPhone, i've just put it down to optus' rubbish network support for the iPhone (reception issues, call drop outs ect...).

On the "phone calling you" side, my voicemail always automatically calls me if someone leaves me a voicemail, and as NathR32 stated, it calls you initially to set it up (did for me anyway). When voicemail calls you it shows up as your number.

I'm with voda and sometimes when listening to voicemail the sound comes through distorted (like it's in fast forward?). This has happened 2 or 3 times, but only with voicemails not with any other calls. Odd...
Vodafone voicemails also show up as your own number trying to call you, I saved my own number as a contact and named it Voice Mail.

It definitely wasn't sped up - just very very warped and evil sounding. Not staticy either. It was voicemail calling me, but I think it was just a one-off network error. I've recorded a silent name and greeting and fingers crossed the damn thing will stop calling me :P

Well, with Vodafone, you receive a call from your own number when you have voice msg as Joey1983 said. Might be something like that.

Optus do not have a call-back function. And the OP has said he hasn't given anyone the number as he's just waiting for the phone to be unlocked.

It could be Optus calling you to setup voicemail regardless, having some kind of network failure, and the system automatically re-dialling you as it has detected your voicemail is still not setup. Either that or it's just general strangeness. I've never had this happen on Optus before.

Guys I sorted it

It was just voicemail calling every hour to set up my greeting. I believe it was a one-off that caused the warped sounds. I waited for the next call, went through the motions, recorded a blank greeting and then hung up. Hasn't called back since.

Although, considering the sounds that were coming out of it I put it on speaker-phone and now my iPhone is known as the SatanPhone rather than JesusPhone

iPhone the new good versus evil battleground, coming soon to a church near year

this isnt quite the same, but every now and again my iphone says "your sim sent a text message" which is weird.