여기 저기 한참 찾아보니 있었네요.^^


function GetLocalIP: string;
var
  wsaData: TWSAData;
  slocal: string;
  hos: PHostEnt;
  addr: PChar;
begin
  result := '';
  if WSAStartup($101, wsaData) <> 0 then exit;
  SetLength(slocal, 256);
  if gethostname(PChar(slocal), 256) = SOCKET_ERROR then exit;
  hos := gethostbyname(PChar(slocal));
  if hos = nil then exit;
  addr := (hos.h_addr_list)^;
  result := IntToStr(Byte(addr[0])) + '.' + IntToStr(Byte(addr[1])) + '.'
    + IntToStr(Byte(addr[2])) + '.' + IntToStr(Byte(addr[3]));
  WSACleanup;
end;