[[escafandra]]

void Folders(String Dir, TStrings* Salida)
{
    TSearchRec sr;
    if(!FindFirst(Dir + "\\*.*", faAnyFile, sr))
    do{
      Salida->Add(Dir + "\\" + sr.Name);
    } while (!FindNext(sr));
    FindClose(sr);
}

void __fastcall TForm1::Button1Click(TObject *Sender)
{
   Folders("C:\\Documents and Settings", Memo1->Lines);
}

Saludos.