Haleemah breastfed the Prophet (peace be upon him) until he was weaned. And he remembered this as a favor from her.

Abu At-Tufayl said:

“I saw the Prophet (peace be upon him) distributing meat in Al-Ji’irraanah. A woman came to him and the Prophet stretched out his cloak for her (to sit on). When I asked who she was, it was said that she was his mother who had breastfed him (i.e. his mother through breastfeeding).” (At-Tabarani)

She was Haleemah bint Abu Thu’ayb Abdullah As-Sa’diyyah (may Allah be pleased with her). She was the wet nurse of the Prophet (peace be upon him).

Haleemah came to Makkah in quest of a baby to breastfeed. This was in a year of drought for her tribe, Banu Sa’d, so the women of the tribe, including Haleemah, set out seeking sustenance. They went to Makkah where people used to entrust their babies to the care of other women.

Haleemah related her story, saying:

“I arrived in Makkah with some women from Banu Sa’d, looking for suckling (kids) in a year of drought and I was riding a weak female donkey. There were a young baby-boy (i.e. her son) and an old she-camel with me.

By Allah, we could not sleep that night because our baby kept weeping bitterly from hunger. There was no milk in my breasts or the breast of the she-camel to give him.

We moved in this state until we reached Makkah, and the caravan had arrived there before us. I went to the Prophet (peace be upon him) and took him, (and he was the only one left).

Once, I returned to my mount with him, the milk gushed in my breasts and his brother (through suckling) was suckled to his fill.

Moreover, my husband found the she-camel full of milk, so he milked it and we all drank to our fill. We spent the night in a state of plenty.

My husband said to me:

‘O Haleemah, I swear by Allah, I think that you brought us a blessed being. Do you not see the goodness and blessing we had this night since we took him?’”

Haleemah was trustworthy in taking care of the Prophet and showered him with love. She (may Allah be pleased with her) never treated him unfairly with her own children, nor did the Prophet find any sort of unequal treatment.

She had children from her husband Al-Harith ibn Abdul-Uzza, who were the suckling siblings of the Prophet. Their names were: Abdullah, Unaysah and Huthafah (also known as Ash-Shaymaa’ (may Allah be pleased with her).
The Prophet used to visit Haleemah and give her gifts to express his gratitude to her, for he stayed with her for four years during which he was raised on the Arabian values of magnanimity, chivalry, truthfulness and honesty. After that, Haleemah (may Allah be pleased with her) brought him back to his mother, Aminah bint Wahb, at the age of five and one month.

The Prophet loved Haleemah so much that when a woman delivered him the news of her death after the conquest of Makkah, his eyes were filled with tears for her (may Allah be pleased with her).

Source: http://www.islamweb.net.