var contentItem = args.DataItem;
var contentDatabase = contentItem.Database;
var contentWorkflow = contentDatabase.WorkflowProvider.GetWorkflow(contentItem);
var contentHistory = contentWorkflow.GetHistory(contentItem);

//Get the workflow history so that we can email the last person in that chain.
if (contentHistory.Length > 0)
{
    //contentWorkflow.GetCommands
    var status = contentWorkflow.GetState(contentHistory[contentHistory.Length - 1].NewState);

    //submitting user (string)
    string lastUser = contentHistory[contentHistory.Length - 1].User;

    //approve/reject comments
    var message = contentHistory[contentHistory.Length - 1].Text;

    //sitecore user (so we can get email address)
    var submittingUser = sc.Security.Accounts.User.FromName(lastUser, false);
}

public void Process(WorkflowPipelineArgs args)
{
    //all variables get initialized
    string contentPath = args.DataItem.Paths.ContentPath;
    var contentItem = args.DataItem;
    var contentWorkflow = contentItem.Database.WorkflowProvider.GetWorkflow(contentItem);
    var contentHistory = contentWorkflow.GetHistory(contentItem);
    var status = "Approved";
    var subject = "Item approved in workflow: ";
    var message = "The above item was approved in workflow.";
    var comments = args.Comments;

    //Get the workflow history so that we can email the last person in that chain.
    if (contentHistory.Length > 0)
    {
        //submitting user (string)
        string lastUser = contentHistory[contentHistory.Length - 1].User;
        var submittingUser = Sitecore.Security.Accounts.User.FromName(lastUser, false);

        //send email however you like (we use postmark, for example)
        //submittingUser.Profile.Email
    }
}