I am on my second iPhone 4S and have the same issue. By accident I put the phone up to my ear thinking I had placed a call and I can here the interference even when not on a call. It seems the static noice is amplified when on a call.
Had a massive fight with Vodafone over the first phone that had the issue, cant be bothered dealing with it again, will just wait the 12 months and get the new iPhone next year.
Hello again everybody,
It's been a good month since checking on this thread, so all the responses were quite a surprise.
I ended up swapping my phone at the Genius bar this past weekend. The new unit still has a very slight ticking or crackling noise, but it's NOTICABLY better than my initial phone. Not sure if it's just a manufacturing variance or my first unit really was that defective. Bottom line is that its actually pretty difficult to detect the noise in my new one (and downright impossible if there's any other ambient noise). In other words, I'll be keeping this one.
Good luck to everyone else!