Ubuntu Multimedia :: Audio Formats: Identification - Conversion - Figure Out What Format A File Is In?

I think that the biggest problem that I have had is that some of the music (and audio books) that I have gotten have not played on my walkman, or have not been able to be downloaded in to I-tunes.

First: I hate itunes... I only try to make it work because I love my wife. (and do not want her to hit me)

Second: I know that my Walkman has a very limited range of files that it can play, so I will need to convert some types of files.

But my basic questions:

* How can I figure out what format a file is in?
* Below that, how can I identify the singular characteristics of a file? (bit rate, and other formats...)
* Is there a best way to switch the formats or format options of these files. (I am currently using sox to do this, it seems to very complete)

Basically. I know nothing! The most that I do not know is that two files that as far as I can tell have the same formats, and should work the same never the less, one of them works, the other does not. I am looking to figure out a way to look at these files (maybe they are mislabeled) and figure out what their real format is (and a more complete format than just being MP3 or such) and then to be able to convert it in to a format that is able to be used by myself and/or my wife.