I feel that mobile imaging could be coming to age. It started with my Nokia N93 cause it had a decent camera. I took a number of ok images. It had a 3.2megapixel camera and a decent lens. It did not perform well in low light or challenging focusing condition, but given good condition you could get a very nice image out of the N93.
Now I have a Nokia N95. It's the older model, not the 8gig model. I have found it to be a reliable phone and the camera now with 5 megapixels works very well. The best thing I did for the phone was upgrade to the latest firmware. That really made the phone super stable. But on to the camera. They have improved not only the size of image that it take but it's less fidegty about non ideal situaltions. It still suffers in low light but not as bad as the N93.
One of the best part of the mobile imaging package is gps and the ability to geotag your photos. With geotagged photos, when you upload them to flickr or picasa, you can locate them on a map.
I had a student whose final year project was about geotagging mobile imagerey, I blame him, I am hooked. Have a look at a google map I created and you'll see why I enjoy this so much.
My N95 Images, geotagged on my google map
So can a mobile phone replace a camera? Yes it can replace most point and shoot digital cameras. No it could not replace a good digital slr. I really enjoy photography. I have had some great cameras in the past. The biggest problem with proper slr's or digital slr's is you don't always have your camera with you, but you always have your phone with you.
Have a look at the above link. As you can see the N95 does a darn good job with the images. I keep running into cloudy days (welcome to England), but overall you can get a decent image. Would I liked to have used a Nikon D80? yes probably, but would I have liked to lug it around with the grandkids all around, no.
The n95 has in built gps and i downloaded an application called location tagger. It does what it says, adds location data to the images in the exif data. Flickr is dead easy to use. Upload your photos and look on the map, Everything is nicely placed on the map in the correct gps position, go nokia n95!!!! Picasa also works once you work out how to upload the photos and keep the location data.
The cool thing about picasa is once you organize your photos, go to view map. While your in map view there is a "view in google earth" option. This exports a kml file. Then if you want to make a google map, , import the kml file and voila you have your photos correctly geotagged and placed in google maps.
Mobile imaging will never replace a good digital slr (will I regret saying that?) There are some things you just can't capture even with a good camera phone. But under the right conditions, you can take interesting, even very good photographs with your camera phone. And if your a nut case like me, enjoy the geotagging side of it