A CBR file is a compressed file of images, most commonly associated with digital comic books. While the iPhone does not natively support CBR files, there are a number of third-party iOS applications that do. Apple now allows for the transferring of files directly to applications via iTunes, making the process of moving CBR files to your phone easier.
Turn on the iPhone. Tap the "App Store" icon. Download an application capable of reading CBR files. IComicViewer, ComicZeal and ComiXology are all such applications.
Plug the iPhone USB cable into the dock connector on the bottom of the phone. Plug the remaining end in to your computer's USB port to tether the two. Double click "iTunes" on the computer.
Click the iPhone and click "Sync," if syncing doesn't occur automatically.
Click the "Apps" tab while the iPhone is still selected. Scroll down to the "File Sharing" section.
Click the CBR reader app in the left-hand column, and drag the CBR files to right-hand column. iTunes automatically transfers the CBR files to the iPhone as they are added. Once copied to the device, you can browse and open the files within the selected applications.