how to record from mic
 

I use fedora core 5 on a toshiba portege laptop, i need to be stick a mic into laptop and record live audio, prefabley in mp3 format

any ideas

I suppose, you can install Audacity for Fedora Core 5 from here

Find out the settings of volume control, in case you are using KDE. They tend to be mute or pretty low, and you have to keep them to the highest level to ensure, you listen to what you speak over the microphone.

Though you cannot actually record in mp3 format, you can export your recording to a mp3(Lame) format, by installing a dll that would help you do the same