http://www.mp3-box.org/convert-ogg-to-mp3-ubuntu/
What audio format should I use?
I used to use Windows media player to rip music and sync it to my Sansa mp3 player. The result is that my entire music collection is in WMA format. I just got an ipod touch, and I realize that I have to convert my music to a different format; however, I have an aversion to the itunes AAC format. Really I just don’t like the fact that there is not much support for it by many of the the standard linux audio players (I currently am using both Windows and Ubuntu.) So here’s my question: other than the iTunes format, what formats should I use to convert all my WMA music files so that they will be supported on my itouch? MP3, Ogg Vorbis, flac, wav., ect. What is your personal preference and why?
As Awesome as it would be to use Ogg Vorbis. It isn’t supported by Apple players (boo!)
I would suggest re-ripping all of your CDS as FLAC, because
A) Converting from a Lossy Format to another Lossy format will end up in a butchered file (it will cut out parts of the file and it will sound really bad)
B) You will have perfect digital copies ready to convert into any codec you wish 
I would also reccomend MP3 for the iPod. As EVERYTHING can play Mp3 Well, except for maybe a toaster….
OS Solutions – Convert MP3 to OGG in Ubuntu