Flickup is an application for uploading photos to Flickr directly from iPhone using the same interfaces as the built-in camera and photo albums applications.
With Flickup, you can geotag photos with one touch and set defaults for even quicker uploads. Want to organize or share your photos? Add them to your favorite sets and groups. You can also send links to your photos directly to your preferred Twitter client (Twitterrific, Twinkle and Tweetie currently supported).