Download and install Audacity, the link to which can be found in the "Resources" section of this page. Follow the download instructions, and click "OK" to install.
Open Audacity. Click "New Project" under the "File" heading, then go to "Save As" under the "File" heading and select a place where your project will be saved. If this step is not taken, the files will be saved to a default location set in Audacity's "Preferences."
Connect your microphone to the correct port on your computer. Select your microphone in Audacity's "Preferences" folder in the audio input section. If you want the recording to be in stereo, select the number "2" under "Channels" in the "Audio I/O" section. Click "OK" to save, then exit "Preferences."
In Audacity's main window, press the record icon (the red circle) to begin your voice recording. When you are finished, press the stop icon (the square).
When you are satisfied with your recording, export the file to your computer by clicking "Export" under the "File" heading. Your file will be saved in the .ogg file format.
In iTunes, go to "File," then "Add to library..." Select the voice recording you saved.
In iTunes "Preferences" folder under the "iTunes" heading, click"'Import Settings" in the "General" section. Make sure that the "MP3 encoder" is selected from the drop-down menu, then press "OK" to exit.
Right-click on your voice file in the iTunes library. Select "Make mp3 Version" from the list. An mp3 copy will be made of your file.