From Forum Nokia Wiki

Many a times it is needed to show updates on wait notes. This can be achieved with the following:

The resource file

RESOURCE DIALOG r_waitnote
{
flags = EAknWaitNoteFlags;
buttons = R_AVKON_SOFTKEYS_CANCEL;
items =
{
	DLG_LINE
	{
		type = EAknCtNote;
		id = EGeneralNote;
		control = AVKON_NOTE
		{
			layout = EWaitLayout;
			singular_label = "Receiving File  : %d Bytes";
			plural_label ="%d %% Recieved";
			imagefile = "z:\\system\data\avkon.mbm";
			imageid = EMbmAvkonQgn_note_progress;
			imagemask = EMbmAvkonQgn_note_progress_mask;
			animation = R_QGN_GRAF_WAIT_BAR_ANIM;
		};
	}
};
}

Here singular_label is what will be shown as soon as the dialog is executed. To change the label CAknWaitNotes SetTextL function is used.

C++ Code

• Create and Execute the dialog

iDlg = new(ELeave)CAknWaitDialog( (REINTERPRET_CAST(CEikDialog**,&iDlg))); 
iDlg->SetTone( CAknNoteDialog::EConfirmationTone ); 
iDlg->SetCallback( this );
iDlg->SetTextL(_L("Please Wait..."));
iDlg->ExecuteLD(R_WAITNOTE);

• Change label as and when required

_LIT(KFormat,"%d %% Recieved");
str.Format(KFormat,kb);
iDlg->SetTextL(str);

• Dismiss the dialog

if(iDlg)
{
iDlg->ProcessFinishedL(); 
iDlg = NULL;
}