The muezzin, a man appointed to call to prayer, climbs the mineret of the mosque, and he calls in all directions, "Hasten to prayer." Many mosques no longer require the muezzin to climb the mineret. Instead, a loud speaker carries the message.
The call to prayer is called the Adhan, Athan or Azan and goes summink, like....
1 Allah u Akbar, Allah u Akbar
-- Allah is Great, Allah is Great
2-Ash-hadu al-la Ilaha ill Allah - Ash-hadu al-la Ilaha ill Allah
-- I bear witness that there is no divinty but Allah
3 Ash-hadu anna Muhammadan Rasulullaah
-- I bear witness that Muhammad is Allah's Messenger
Ash-hadu anna Muhammadan Rasulullaah.
-- I bear witness that Muhammad is Allah's Messenger
4 Hayya la-s-saleah - Hayya la-s-saleah
-- Hasten to the prayer, Hasten to the prayer
5 Hayya la-l-faleah - Hayya la-l-faleah
-- Hasten to real success, Hasten to real success,
6 Allahu Akbar, Allahu Akbar
-- Allah is Great, Allah is Great
7 La Ilaha ill Allah
-- There is no divinity but Allah