There are many programs out there that will take in both CD or WAV audio and output an MP3 file.
If you are looking for ease of use with a straightforward user interface, here are a few programs you could use:
Music Match JukeBox is available from MusicMatch www.musicmatch.com](www.musicmatch.com) for free to download. With this program you can directly convert CD audio or WAV files to high quality MP3 files.
Another program free program which converts WAVs to MP3 is RazorLAME available to download at
http://www.dors.de/razorlame