Executa uma url com o browser padrão

Procedure ExploreWeb(page:PChar);
// Requer a ShellApi declarada na clausua uses da unit
var
Returnvalue : integer;
begin
ReturnValue := ShellExecute(0, 'open', page, nil, nil,SW_SHOWNORMAL);
if ReturnValue <= 32 then
begin
case Returnvalue of
0 : MessageBox(0,'Error: Out of memory','Error',0);
ERROR_FILE_NOT_FOUND: MessageBox(0,'Error: File not found','Error',0);
ERROR_PATH_NOT_FOUND: MessageBox(0,'Error: Directory not found','Error',0);
ERROR_BAD_FORMAT : MessageBox(0,'Error: Wrong format in EXE','Error',0);
else
MessageBox(0,PChar('Error Nr: '+IntToStr(Returnvalue)+' inShellExecute'),'Error',0)
end;
end;
end;