If your computer is connected to a microphone, you can use FirstClass to record a spoken message, or any other sound, and attach this recording to a message as an MP3 file.         Notes You can also attach existing MP3, AIFF and WAV files, and Mac OS resource files with system 7 SND resources. WAV and AIFF files can contain many audio formats, such as PCM, ADPCM, IMA-ADPCM, MULaw, A-LAW, and so on. In addition, you can embed sound files in content. Depending on your preferences, attached sound files may play automatically when you open an unread message. To use your microphone to attach a recording to a message: 1       Choose Edit > Insert > Insert Voice with the message open. A voice player pane is added to the message envelope. This button Does this Records. Stops the recording and attaches the sound file. Plays the recording. Stops playback. Controls the volume. Positions the voice player. 2       Click Record. 3       Use your microphone to record your message or sound. 4       Click the stop recording button when you are finished recording. A sound file is attached to the message envelope. To review the recording, click the play button. To change the recording, delete the attachment and click Record again. You can also attach an additional recording by clicking Record again.