fre:ac Portable version is an audio encoder you can run from your USB pen drive.
If you want to convert an audio file or files to MP3, Ogg, AVI or WAV format, you can use fre:ac Portable. It's especially useful for converting FLAC files to MP3, as iTunes doesn't support that open source lossless sound format.
fre:ac Portable also rips CDs to the format of your choice. While what it does is fairly simple, fre:ac is not really user friendly. The settings are awkward, and while it will do for most of your audio conversion needs, the interface is really old fashioned and clunky.
Conversions are good, despite fre:ac Portable's aging appearance. If you are a fan of lossless sound formats (the files are big, but the quality is perfect), it's good to have a FLAC encoding tool, which is so lightweight. When ripping CDs, fre:ac Portable will find meta data from the CDDB database, so you shouldn't ever have to enter song names and so on yourself.
fre:ac Portable is a small encoding tool that does it's job well, it's just a shame the interface is so off putting.