Also, you can use this function:
Code:
BOOL SetDlgItemText(
  HWND hDlg,         // handle to dialog box
  int nIDDlgItem,    // control identifier
  LPCTSTR lpString   // text to set
);
Bit of a time saver really:
Code:
SetDlgItemText(hWnd_MyWindow, IDC_BUTTON, "New caption");