Just got back from holidays and my iphone 4 ended up sliding off the boat in big waves into the ocean, luckily i dived in and just grabbed it with the tips of my fingers. I've taken it apart and sanded down some corrosion/brushed off things that were trying to grow in it. Booted it up again just enough to get my 300 island/surfing photos off it.
the battery is shot along with the home button, speaker/mic and camera. I've ordered these parts from ebay hopefully should be here soon.
I also have an unlocked ipad2 running on bMobile (docomo), after reading this thread, i put my softbank ip4 sim into my ipad2, and it says this device is not registered to run this simcard, (error 0006#). I suppose that means the sim is locked to iphone 4, or just iphone/ipad devices purchased in Japan.
if you do want to use your unlocked phone/ipad in japan, i suggest bMobile prepaid, can be purchased in 6 or 12month blocks.