Drama classes and/or dialect classes are very helpful. it helps to know someone, to get in with a vo company. also, the other girl that answered has no idea what she actually is talking about. once you find a VO studio, you can just audition for them, voice over sites in man. once you have booked some work, you can put together a reel from your existing jobs. you do NOT need to pay tens and thousands of dollars to "create" a fake reel. MOST voice actors come from many years in theatre and movie, so arrive at class.
For more info visit: http://voicesonlinenow.com
Source: voice acting jobs, voice acting, voice over websites