[Perio]

Proba con esto:

Código Delphi [-]
procedure TForm.irURLExecute(Sender: TObject);
var
  DirWeb: string;
begin
  DirWeb:= 'http://www.Clubdelphi.com';
  ShellExecute(Application.Handle, nil, PChar(DirWeb), '', '',SW_SHOWNORMAL);
end;