Make sure you have a microphone installed on your computer. Many computers come with built-in microphones. If you don't have one you can purchase an external microphone from your local electronics or music store.
Visit a website that will allow you to use their online software to create your music project. JamStudio.Com and HobNox.Com are just two such websites that offer free downloads.
Sign up for a free user account. For Jam Studio you will click on the "Join" option at the top of the page. For HobNox, click on the "Register" link that is located in the top left-hand corner of the HobNox homepage.
Begin creating beats for your song; the software makes it easy for you to play with your song's tempo. Customize your music by adding instrumentation, such as guitar, drums and piano, and try out the effects tools to add distortion or change the sound of an instrument.
Once you have the instrumentation complete, add vocals. Click on the "Record" icon. For JamStudio, the "Jam Recorder" icon will be located on the bottom left-hand side. You must download and install Jam Recorder before you can use the recording software. For HobNox, click on the cassette tape icon that is located in the top left-hand side. Sing into your computer's mic to record the vocals to your song.
Save your song once you have finished recording. You should be able to save the project in an MP3 format, which will allow you to share the file with friends directly or to burn the song to a CD.