Create a website. The online audition tape should revolve around a custom website where people can come and find out all about you. This means a real website, not a Myspace, Soundclick, or Reverb Nation page. Those things should help support your website where most of your music lives. Services like Bandzoogle or Hostbaby have affordable website hosting packages geared specifically towards musical artists and songwriters.
Write a compelling bio. Depending on if you're a music artist or songwriter, having pertinent information relating to your experience in music is a plus. However, remember that this showcases your professionalism rather than your music. The only thing that it can do is slightly increase the chances of your demo being listened to. Post this to your website.
Record at least three good original songs. This may go without saying, but make sure that your demos are up to snuff. With DAWs (digital audio workstations) being affordable and intuitive to use, a well equipped home studio is enough to produce a top quality demo. Don't cut corners here. The demo takes the place of you being there and is the star of the interview process. Make sure it shines.
Upload the songs. The most popular and secure way to listen to songs online is with a Flash player that has your songs queued and ready to play simply by clicking on them. Have your three strongest songs listed first.
Write an email. This should be composed as a cover letter and meet all the specifications of the guidelines the company has laid out. Tell them a little about yourself then refer them to your website where they can hear your music.