Fasting Hadith :1

ahih Bukhari :: 31:115
Narrated Talha bin ‘Ubaid-Ullah: A bedouin with unkempt hair came to Allah’s Apostle and said, “O Allah’s Apostle! Inform me what Allah has made compulsory for me as regards the prayers.” He replied: “You have to offer perfectly the five compulsory prayers in a day and night (24 hours), unless you want to pray Nawafil.” The bedouin further asked, “Inform me what Allah has made compulsory for me as regards fasting.” He replied, “You have to fast during the whole month of Ramadan, unless you want to fast more as Nawafil.” The bedouin further asked, “Tell me how much Zakat Allah has enjoined on me.” Thus, Allah’s Apostle informed him about all the rules (i.e. fundamentals) of Islam. The bedouin then said, “By Him Who has honored you, I will neither perform any Nawafil nor will I decrease what Allah has enjoined on me. Allah’s Apostle said, “If he is saying the truth, he will succeed (or he will be granted Paradise).”

When to start fasting...

Ibn Umar related that the Prophet said: Do not start fasting unless you see the new moon, and do not end fasting until you see it. If the weather is cloudy then calculate when it should appear (Bukhari, Muslim).

DUA for FIRST ASHRA first ten days of the Blessed Month of Ramadan

Rab-bigh-fir war-ham wa Anta Khair-ur-Raahimeen. (Surah Al Muminun:118)

My Lord! Forgive and have mercy, for You are the Best of those who show mercy!

Ya Rabb, Allahumma arhamni Ya Arham-mar-Rahimeen.

Ya Hayyu Ya Qayyumu Birahmatika asta-ghee-thu.

 We should seek Allah's Mercy in these days.

Dua for breaking a fast at a friends house

Aftara 'indakumus saa'imuna, wa akala ta'aamakumul-abraaru, wasallat 'alaikumul mala'ikat 
May fasting people break their fast by You and may pious persons partake of Your food and may the angels invoke Allah's blessings for You

Dua for breaking a fast at the time of Iftaar

Allahumma inni laka sumtu wa bika aamantu [wa 'alayka tawakkaltu] wa 'ala rizq-ika aftarthu 
O Allah. I fasted for You and I believe in You and I break my fast with Your sustenance

Dua for keeping a fast at the time of Sahar

Wa bisawmi ghadinn nawaiytu min shahri ramadan
I intent to keep fast today for the month of Ramadaan

The Hadith On Fasting

Abu Huraira related that the Prophet (peace and blessings be upon him) said: Whoever fasts during Ramadan with faith and seeking his reward from Allah will have his past sins forgiven. Whoever prays during the nights in Ramadan with faith and seeking his reward from Allah will have his past sins forgiven. And he who passes Lailat al-Qadr in prayer with faith and seeking his reward from Allah will have his past sins forgiven (Bukhari, Muslim).
Abu Huraira related that Rasulullah said: If anyone omits his fast even for one day in Ramadan without a concession or without being ill, then if he were to fast for the rest of his life he could not make up for it (Bukhari).
Abu Huraira related that the Prophet said: Allah the Majestic and Exalted said: "Every deed of man will receive ten to 700 times reward, except Siyam (fasting), for it is for Me and I shall reward it (as I like). There are two occasions of joy for one who fasts: one when he breaks the fast and the other when he will meet his Lord" (Muslim).
Abu Huraira related that Rasulullah said: Many people who fast get nothing from their fast except hunger and thirst, and many people who pray at night get nothing from it except wakefulness (Darimi).