Transfer files from computer to iphone without using iTunes
Read 3 Ways to Transfer MP3 to iPod with or without iTunes.

tldr :


on Mac or Windows: SyncPod. But ... 


  This product currently is incompatible with Mac OS X Lion 10.7 or iOS 5.

on Linux or Windows : MediaMonkey  


  Any version of MediaMonkey 4 can sync with any iPod, iPad, or iPhone
  (including the iPhone 5) via the following addon:
  http://www.mediamonkey.com/addons/browse/item/device-plugin-for-itunes/