Well, for .wav to mp3...
Been a while since I've converted any .wav files to mp3, but for simplicity ya can't beat a program called Blade Encoder. Unfortunately, the fella that wrote it took it down after being pressured by 'the system'. Figured it was BS, but just another case of big money threatening the little guy, justified or not. You can probaby do a web search and find copies of it floating around.
Anywho...all you haff to do is drag and drop a .wav file to the Blade icon and it opens a small DOS window showing you the time left for mp3 conversion. When through, the box closes and you have your original .wav file and identical .mps file.
No buttons, windows, learning curve, yadda yadda yadda.
Nuttin' wrong with simplicity!