Determine your compression needs. If you need a fast file and you are not concerned with losing a bit of audio quality, you should use the LAME mp3 codec, which is available for free download on the web. If you would be willing to have a slightly larger file which has higher quality audio, you need to get an MP4 codec like in Nero. Also, 3ivx makes a free MP4 codec that is available for download online.
Download and save your new audio compression codec in a file folder which you can easily access, as you will need it later.
Locate the audio files you wish to compress. Load the audio files into your Foobar 2000 playlist. In newer versions of Foobar 2000, you can simply drag and drop the audio files from their file folder to the playlist. If you have done this correctly, you should now see a list of files in the main window of the Foobar 2000 application.
Using your cursor, select the songs that you loaded into the playlist menu by highlighting them. You can highlight a series of files by grabbing and dragging downward in the playlist window.
When the songs you wish to convert have been successfully selected by the cursor, choose the "Convert to..." option by right-clicking the selected files and finding the "Convert to..." selection in the drop-down menu. At this point, you should see a window that pops up requesting the file type you would like to convert to.
In the pop-up window, choose the audio encoding option you decided was best for your audio situation. Choosing MP3 will give you a smaller, lower quality file, while the MP4 option offers a larger file with better sound quality. You should then encounter a window which requests the location of the *.exe file you downloaded as your audio codec. Locate the file using the "Browse" function and press OK. Foobar should now begin compressing and re-encoding your audio files, resulting in a smaller and more data compressed sound file.