Sunan Ibn Majah Book 34, Hadith 48
the Messenger of Allah (saas) said: "When anyone of you wants to go to bed, let him undo the edge of his Izar (waist wrap) and dust of his bed with it, for he does not know what came to it after him. Then let him lie down on his right side and say: 'Rabbi bika wada'tu janbi wa bika arfa'uhu, fa in amsakta nafsi farhamha, wa in arsaltaha fahfazha bima hafizta bihi 'ibadikaas-salihin (O Lord, by Your leave I lie down and by Your leave I rise, so if You should take my soul then have mercy on it, and if You should return my soul then protect it as You protect Your righteous slaves)."
when going to bed, the Prophet (saas) used to say: "Allahumma Rabbas-samawati wa Rabbal-ardi, wa Rabba kulli shay'in, faliqal-habbi wan-nawa, munzilat-Tawrati wal-Injili wal-Qur'anil-'Azim. A'udhu bika min sharri kulli dabbatin Anta akhidhun binasiyatiha, Antal-Awwalu fa laysa qablaka shayun, wa Antal-Akhiru, fa laysa ba'daka shayun', Antaz-zahiru, fa laysa fawqaka shayun', wa antal-batinu fa laysa dunaka shay', aqdi 'annid-dayna waghnini minal-faqr (O Allah, Lord of the heavens and Lord of the earth and Lord of all things, Cleaver of the seed and the kernel, Revealer of the Tawrah, the Injil and the Magnificent Qur'an, I seek refuge with You from the evil of every creature You seize by the forelock. You are the First and there is nothing before You; You are the Last and there is nothing after You; You are the Most High (Az-Zahir) and there is nothing above You, and You are the Most Near (Al-Batin) and there is nothing nearer than You. Settle my debt for me and spare me from poverty)."
whenever the Prophet (saas) went to bed, he would blow into his hands, recite Al-Mu'awwidhatain, then wipe his hands over his body.