I have an original iPhone - the 2G - and am debating upgrading to the iPhone 4 (as of September 2011, which means I had my original iPhone for almost four years) almost entirely for the camera functions. Ok, and the speed, capacity, gps, video, compass and on and on...
The apps I use for iPhone shots are Click! (link takes you to the App Store) to take colour pictures and Vint B&W for the Black and whites. I had a list of photo apps here that I use but that list is so long now there's no point. I try to list the apps used in the photo's description. I also use Tumblr's iPhone app for posting so this is an all iPhone deal. I should also list a non-photography related app that has quickly become invaluable for clipboard operations: Pastebot.
No desktop/laptop needed for any of the photos posted here.