I don't think you'll get much better than Audacity as a free editing program. It can open & save into mp3 formats & ogg vorbis & WAV. http://audacity.sourceforge.net/windows.php BTW the manual, plug-in enabler for VST plug-ins, etc. are separate downlds so look carefully!

It allows you to record from external sources, to normalise, to apply FX such as noise reduction, etc.