Usually, a diversion program (where you do community service) results in a conviction being dismissed. For example, you plead guilty to the crime, do the community service, then the judge dismisses your conviction. The end result is that you can say "NO" to the question, 'have you ever been convicted of a crime?'
Expungement is usually reserved for those who have been incorrectly ACCUSED of a crime. For example, you are accussed of rape, your goto trial, and are acquited, OR the prosecutor dismisses the charges. Prior to this occuring, you may have been finger printed and/or photographed. Expunging your record will result in those records being destroyed or at least removed from the publics view. BUT, if you've been convicted of a crime (and even if you did the diversion program), you generally can't have your conviction expunged (again, it's primarily for the innocent).
My advice is free, but it's based on what I know about the state of Virginia. You should definitely ask a lawyer for advice who knows the laws in your state. Alternatively, you can sometimes get good advice from google's answer service.
Good luck.