I have ran into this problem a few times and was wondering what i can do to fix it or get around it. When i put an .M4b file on my iPhone 4 I usually don't have a problem, but if the file is rather long, the phone won't show it in the IPod. I know it has to do with the length of the file. The two I'm running it to the problem with now are 96.2 MB and 5:59:58 long, the other file is 105 MB and 6:34:31 long. Is there away around this?