Автор: http://delphi.mastak.ru

var
  Computer: array[1..500] of string[25];
  ComputerCount: Integer;

procedure FindAllComputers(Workgroup: string);
var
  EnumHandle: THandle;
  WorkgroupRS: TNetResource;
  Buf: array[1..500] of TNetResource;
  BufSize: Integer;
  Entries: Integer;
  Result: Integer;
begin
  ComputerCount := 0;
  Workgroup := Workgroup + #0;
  FillChar(WorkgroupRS, SizeOf(WorkgroupRS), 0);
  with WorkgroupRS do
  begin
    dwScope := 2;
    dwType := 3;
    dwDisplayType := 1;
    dwUsage := 2;
    lpRemoteName := @Workgroup[1];
  end;
  WNetOpenEnum(RESOURCE_GLOBALNET,
    RESOURCETYPE_ANY,
    0,
    @WorkgroupRS,
    EnumHandle);
  repeat
    Entries := 1;
    BufSize := SizeOf(Buf);
    Result :=
    WNetEnumResource(EnumHandle,
      Entries,
      @Buf,
      BufSize);
    if (Result = NO_ERROR) and (Entries = 1) then
    begin
      Inc(ComputerCount);
      Computer[ComputerCount] := StrPas(Buf[1].lpRemoteName);
    end;
  until (Entries <> 1) or (Result <> NO_ERROR);
  WNetCloseEnum(EnumHandle);
end; { Find All Computers }