Here in Japan EVERYBODY has cell phones. You can't even have a social life if you don't have one. The development of cell phone technology is way beyond that of anything anywhere else in the world, especially because far more Japanese (and Asians) use the internet through cell phones than through desktop computers.
My cell phone has 3 MB px (very common here... it is the 6 MB px camera phones and the television phones, GPS phones and international dialing phones that are all the rage at the moment) and it takes very sharp and impressive photos.
However, I would never use the camera for hiking because the battery life is dismal. Within twenty minutes of continuous shooting the cell phone goes dead. It is just not reliable out away from power sources.
Since I am a diabetic I carry the phone for emergencies when I hike but never use it on the trail. Back in the cities I will use it to look up train and bus schedules on the internet and to e-mail friends for meet ups. IF you're serious about photography, though, I would recommend against it.
My ¥2.0's worth...