This was MUCH easier to accomplish than ADSI info gathering.  Code is below:

    public bool IsMemberOf(string szGroupName)
    {
        System.Security.Principal.WindowsPrincipal user =
            (System.Security.Principal.WindowsPrincipal)HttpContext.Current.User;
        bool bVal = user.IsInRole(szGroupName);
        return (bVal);
    }