A:  This code should draw all the entries in a listbox as red.  (Don't forget to change the Listbox's style to lbOwnerDrawFixed.)

procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState); VAR
  S : String;
  Temp: array[0..255] of Char;
begin
  WITH Control AS TListBox, Canvas DO
    BEGIN
      S := Items[Index];
      FillRect(Rect);
      MoveTo(Rect.Left+2, Rect.Top);
      SetTextAlign(Canvas.Handle, TA_LEFT OR TA_UPDATECP);
      Font.Color := clRed;
      StrPCopy(Temp, S);
      WinProcs.TextOut(Canvas.Handle, 0, 0, Temp, StrLen(Temp));
    END;
end;

{*******************************}

Here is a version that does not use the API call, but does the same thing:

unit Unit1;

interface

uses
  SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
  Forms, Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    ListBox1: TListBox;
    procedure FormActivate(Sender: TObject);
    procedure ListBox1DrawItem(Control: TWinControl; Index: Integer;
      Rect: TRect; State: TOwnerDrawState);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormActivate(Sender: TObject);
begin
  listbox1.items.LoadFromFile('c:\autoexec.bat');
end;

procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState);
begin
  WITH Control AS TListBox, Canvas DO BEGIN
    FillRect(Rect);
    MoveTo(Rect.Left+2, Rect.Top);
    SetTextAlign(Canvas.Handle, TA_LEFT OR TA_UPDATECP);
    Font.Color := clGreen;
    TextOut(0, 0, Items[Index]);
  END;
end;

end.